Insectivorous Plants

an immersion of 8 hrs. 20 m. the leaves were washed and placed in water; next morning, after about 16 hrs., they were still inflected and discoloured ; on the succeeding day they were evidently dead. Two leaves were immersed in a stronger mixture, of one part to fifty of water ; in 1 hr. 15 m. the glands became as white as porcelain, as if they had been dipped in boil- ing water ; very few of the tentacles were inflected ; but after 4 hrs. almost all were inflected. These leaves were then placed in water, and next morning were evidently dead. Half-minim drops of the same strength (viz. one part to fifty of water) were next placed on the discs of five leaves ; after 21 hrs. all the outer tentacles were inflected, and the leaves appeared much injured. I likewise touched the secretion round a large number of glands with minute drops (about ^ of a minim, or '00296 ml.) of Scheele's mixture (6 percent.); the glands first became bright red, and after 3 hrs. 15 m. about two-thirds of the tentacles bearing these glands were inflected, and remained so for the two succeeding days, when they appeared dead.

Concluding Remarks on the Action of Acids. — It is evident that acids have a strong tendency to cause the inflection of the tentacles ; * for out of the twenty-four acids tried, nineteen thus acted, either rapidly and energetically, or slowly and slightly. This fact is remarkable, as the juices of many plants contain more acid, judging by the taste, than the solutions employed in my experiments. From the powerful effects of so many acids on Drosera, we are led to infer that those naturally contained in the tissues of this plant, as well as of others, must play some important part in their economy. Of the five cases in which acids did not cause the tentacles to be inflected, one is doubtful ; for uric acid did act slightly, and caused a copious secretion of mucus. Mere sourness to the taste is no

"According to M. Fournier Berberis instantly to close; though (' De la Fecondation dims les drops of water have no siich power, Phanerogames." 18(53, p. 61) drops which latter statement I can cour of acetic, hydrocyanic, and sul- firm, phtiric acid cave the stamens of criterion of the power of an acid on Drosera, as citric and tartaric acids are very sour, yet do not excite inflection. It is remarkable how acids differ in their power. Thus, hydrochloric acid acts far less powerfully than hydriodic and many other acids of the same strength, and is not poisonous. This is an in- teresting fact, as hydrochloric acid plays so important a part in the digestive process of animals. Formic acid induces very slight inflection, and is not poison- ous ; whereas its ally, acetic acid, acts rapidly and powerfully, and is poisonous. Malic acid acts slightly, whereas citric and tartaric acids produce no effect. Lactic acid is poisonous, and is remarkable from in- ducing inflection only after a considerable interval of time. Nothing surprised me more than that a solution of benzoic acid, so weak as to be hardly acidulous to the taste, should act with great rapidity and be highly poisonous ; for I am informed that it produces no marked effect on the animal economy. It may be seen, by looking down the list at the head of this dis- cussion, that most of the acids are poisonous, often highly so. Diluted acids are known to induce nega- tive osmose,* and the poisonous action of so many acids on Drosera is, perhaps, connected with this power, for we have seen that the fluids in which they were immersed often became pink, and the glands pale-coloured or white. Many of the poisonous acids, such as hydriodic, benzoic, hippuric, and carbolic (but I neglected to record all the cases), caused the secre- tion of an extraordinary amount of mucus, so that long ropes of this matter hung from the leaves when they were lifted out of the solutions. Other acids, such as hydrochloric and malic, have no such ten-

dency ; in these two latter cases the surrounding fluid was not coloured pink, and the leaves were not poisoned. On the other hand, propionic acid, which is poisonous, does not cause much mucus to be secreted, yet the surrounding fluid became slightly pink. Lastly, as in the case of saline solutions, leaves, after being immersed in certain acids, were soon acted on by phosphate of ammonia ; on the other hand, they were not thus affected after immer- sion in certain other acids. To this subject, how- ever, I shall have to recur.

Strychnine, salts of — Quinine, sulphate of, does not soon arrest the movement of the protoplasm — Other salts of quinine — Digitaline — Nicotine — Atropiue — Veratrine — Colchicine — Theine — Curare — Morphia, — Hyoscyamus — Poison of the cohra, apparently acce- lerates the movements of the protoplasm — Camphor, a powerful stimulant, its vapour narcotic — Certain essential oils excite move- ment — Glycerine — Water and certain solutions retard or prevent the subsequent action of phosphate of ammonia — Alcohol inno- cuous, its vapour narcotic and poisonous — Chloroform, sulphuric and nitric ether, their stimulant, poisonous, and narcotic power — Carbonic acid narcotic, not quickly poisonous — Concluding remarks.

As in the last chapter, I will first give my experiments, and then a brief summary of the results with some concluding remarks. Acetate of Strychnine. — Half-minims of a solution of one part tc> 437 of water were placed on the discs of six leaves ; so that each received -g^j- of a grain, or .0675 mg. In 2 hrs. 30 m. the outer tentacles on some of them were inflected, but in an irregu- lar manner, sometimes only on one side of the leaf. The next morning, after 22 hrs. 30 m., the inflection had not increased. The glands on the central disc were blackened, and had ceased secreting. After an additional 24 hrs. all the central glands seemed dead, but the inflected tentacles had re-expanded and appeared quite healthy. Hence the poisonous action of strych- nine seems confined to the glands which have absorbed it ; nevertheless, these glands .transmit a motor impulse to tho exterior tentacles. Minute drops (about -^ of a minim) of the same solution applied to the glands of the outer tentacles occasionally caused them to bend. The poison does not seem to act quickly, for having applied to several glands similar drops of a rather stronger solution, of one part to 292 of water, this did not prevent the tentacles bending, when their glands

were excited, after an interval of a quarter to three quarters of an hour, by being rubbed or given bits of meat. Similar drops of a solution of one part to 218 of water (2 grs. to 1 oz.) quickly blackened the glands; some few tentacles thus treated moved, whilst others did not. The latter, however, on being subse- quently moistened with saliva or given bits of meat, became incurved, though with extreme slowness; and this shows that they had been injured. Stronger solutions (but the strength was not ascertained) sometimes arrested all power of movement very quickly ; thus bits of meat were placed on the glands of several exterior tentacles, and as soon as they began to move, minute drops of the strong solution were added. They con- tinued for a short time to go on bending, and then suddenly stood still; other tentacles on the same leaves, with meat on their glands, but not wetted with the strychnine, continued to bend and soon reached the centre of the leaf.

Cerate <f Strychnine. — Half-minims of a solution of one part to 437 of water were placed on the discs of six leaves ; after 24 hrs. the outer tentacles showed only a trace of inflection. Bits of meat were then placed on three of these leaves, but in 24 hrs. only slight and irregular inflection occurred, proving that the leaves had been greatly injured. Two of the leaves to which meat had not been given had their discal glands dry and much injured. Minute drops of a strong solution of one part to 109 of water (4 grs. to 1 oz.) were added to the secretion round several glands, but did not produce nearly so plain an effect as the drops of a much weaker solution of the acetate. Particles of the dry citrate were placed on six glands ; two of these moved some way towards the centre, and then stood still, being no doubt killed ; three others curved much farther inwards, and were then fixed; one alone reached the centre. Five leaves were immersed, each in thirty minims of a solution of one part to 437 of water; so that each received TL of a grain; after about 1 hr. some of the outer tentacles became inflected, and the glands were oddly mottled with black and white. These glands, in from 4 hrs. to 5 hrs., became whitish and opaque, and the protoplasm in the cells of the tentacles was well aggre- gated. By this time two of the leaves were greatly inflected, but the three others not much more inflected than they were before. Nevertheless two fresh leaves, after an immersion re- spectively for 2 hrs. and 4 hrs. in the solution, were not killed ; for on being left for 1 hr. 30 m. in a solution of one part of carbonate of ammonia to 218 of water, their tentacles became more inflected, and there was much aggregation. The glands

of two other leaves, after an immersion for 2 hrs. in a stronger sohition, of one part of the citrate to 218 of water, became of an opaque, pale pink colour, which before long disappeared, leaving them white. One of these two leaves had its blade and tentacles greatly inflected ; the other hardly at all ; but the protoplasm in the cells of both was aggregated down to the bases of the tentacles, with the spherical masses in the cells close beneath the glands blackened. After 24 hrs. one of these leaves was colourless, and evidently dead.

Sulphate of Quinine. — Some of this salt was added to water, which is said to dissolve y^nr Par^ °f ^s weight. Five leaves were immersed, each in thirty minims of this solu- tion, which tasted bitter. In less than 1 hr. some of them had a few tentacles inflected. In 3 hrs. most of the glands became whitish, others dark-coloured, and many oddly mottled. After 6 hrs. two of the leaves had a good many tentacles inflected, but this very moderate degree of inflection never increased. One of the leaves was taken out of the solution after 4 hrs., and placed in water ; by the next morning some tew of the inflected tentacles had re-expanded, showing that they were not dead ; but the glands were still much discoloured. Another leaf not included in the above lot, after an immersion of 3 hrs. 15 m., was carefully examined ; the protoplasm in the cells of the outer tentacles, and of the short green ones on the disc, had become strongly aggregated down to their bases ; and I distinctly saw that the little masses changed their positions and shapes rather rapidly ; some coalescing and again separating. I was surprised at this fact, because quinine is said to arrest all move- ment in the white corpuscles of the blood ; but as, according to Binz,* this is due to their being no longer supplied with oxygen by the red corpuscles, any siich arrestment of movement could not be expected in Drosera. That the glands had absorbed some of the salt was evident from their change of colour ; but I at first thought that the solution might not have travelled down the cells of the tentacles, where the protoplasm was seen in active movement. This view, however, I have no doubt, is erroneous, for a leaf which had been immersed for 3 hrs, in the quinine solution was then placed in a little solution of one part of carbonate of ammonia to 218 of water; and in 30 m.

the glands and the upper cells of the tentacles became intensely black, with the protoplasm presenting a very unusual appearance; for it had become aggregated into reticulated dingy-coloured masses, having rounded and angular interspaces. As I have never seen this effect produced by the carbonate of ammonia alone, it must be attributed to the previous action of the quinine. These reticulated masses were watched for some time, but did not change their forms ; so that the protoplasm no doubt had been killed by the combined action of the two salts, though exposed to them for only a short time.

Another leaf, after an immersion for 24 hrs. in the quinine solution, became somewhat flaccid, and the protoplasm in all the cells was aggregated. Many of the aggregated masses were discoloured, and presented a granular appearance ; they were spherical, or elongated, or still more commonly consisted of little curved chains of small globules. None of these masses exhibited the least movement, and no doubt were all dead. Half-minims of the solution were placed on the discs of six leaves; after 23 hrs. one had all its tentacles, two had a few, and the others none inflected ; so that the discal glands, when irritated by this salt, do not transmit any strong motor impulse to the outer tentacles. After 48 hrs. the glands on the discs of all six leaves were evidently much injured or quite killed. It is clear that this salt is highly poisonous.*

Acetate of Quinine. — Four leaves were immersed, each in thirty minims of a solution of one part to 437 of water. The solution was tested with litmus paper, and was not acid. After only 10 m. all four leaves were greatly, and after 6 hrs. immensely, inflected. They were then left in water for 60 hrs., but never re-expanded; the glands were white, and the leaves evidently dead. This salt is far more eificient than the sulphate in causing inflection, and, like that salt, is highly poisonous.

Nitrate of Quinine. — Four leaves were immersed, each in thirty minims of a solution of one part to 437 of water. After 6 hrs. there was hardly a trace of inflection ; after 22 hrs. three of the leaves were moderately, and the fourth slightly inflected ; so that this salt induces, though rather slowly, well-marked inflec- tion. These leaves, on being left in water for 48 hrs., almost * Binz found several years ago white corpuscles, which become (as stated in ' The Journal of " rounded and granular." In the

1872, p. 195) that quinia is an gated masses of protoplasm, which energetic poison to low vege- appeared killed by the quinine, table and animal organisms. Even likewise presented a granulai one part added to -1000 parts of appearance. A similar appear- blood arrests the movements of the ance is caused by very hot water completely re-expanded, but the glands were much discoloured. Hence this salt is not poisonous in any high degree. The different action of the three foregoing salts of quinine is sin- gular.

Diyitaline. — Half-minims of a solution of one part to 437 of •water were placed on the discs of five leaves. In 3 hrs. 45 m. some of them had their tentacles, and one had its blade, moderately inflected. After 8 hrs. three of them were well in- flected; the fourth had only a few tentacles inflected, and the fifth (an old leaf) was not at all affected. They remained in nearly the same state for two days, but the glands on their discs became pale. On the third day the leaves appeared much injured. Nevertheless, when bits of meat were placed on two of them, the outer tentacles became inflected. A minute drop (about -^ of a minim) of the solution was applied to three glands, and after 6 hrs. all three tentacles were inflected, but next day had nearly re-expanded ; so that this very small dose of 2SSOO of a grain ('00225 mg.) acts on a tentacle, but is not poisonous. It appears from these several facts that digitaline causes inflection, and poisons the glands which absorb a moderately large amount.

Nicotine. — The secretion round several glands was touched with a minute drop of the pure fluid, and the glands were instantly blackened; the tentacles becoming inflected in a few minutes. Two leaves were immersed in a weak solution of two drops to 1 oz., or 437 grains, of water. When examined after 3 hrs. 20 m., only twenty-one tentacles on one leaf were closely inflected, and six on the other slightly so ; but all the glands were blackened, or very dark-coloured, with the pro- toplasm in all the cells of all the tentacles much aggregated and dark-coloured. The leaves were not quite killed, for on being placed in a little solution of carbonate of ammonia (2 grs. to 1 oz.) a few more tentacles became inflected, the remainder not being acted on during the next 24 hrs.

Half-minims of a stronger solution (two drops to i oz. of water) were placed on the discs of six leaves, and in 30 m. all those tentacles became inflected ; the glands of which had actually touched the solution, as shown by their blackness ; but hardly any motor influence was transmitted to the outer tentacles. After 22 hrs. most of the glands on the discs ap- peared dead ; but this could not have been the case, as when bits of meat were placed on three of them, some few of the outer tentacles were inflected in 24 hrs. Hence nicotine has a great tendency to blacken the glands and to indiice aggregation

of the protoplasm, but, except when pure, has very moderate power of inducing inflection, and still less power of causing a motor influence to be transmitted from the discal glands to the outer tentacles. It is moderately poisonous. Atropine.—A. grain was added to 437 grains of water, but was not all dissolved ; another grain was added to 437 grains of a mixture of one part of alcohol to seven parts of water; and a third solution was made by adding one part of valerianate of atropine to 437 of water. Half-minims of these three solutions were placed, in each case, on the discs of six leaves ; but no effect whatever was produced, excepting that the glands on the discs to which the valerianate was given were slightly discoloured. The six leaves on which drops of the solution of atropine in diluted alcohol had been left for 21 hrs. were given bits of meat, and all became in 24 hrs. fairly well inflected ; so that atropine does not excite movement, and is not poisonous. I also tried in the same manner the alkaloid sold as daturine, which is believed not to differ from atropine, and it produced no effect. Three of the leaves on which drops of this latter solution had been left for 24 hrs. were likewise given bits of meat, and they had in the course of 24 hrs. a good many of their submarginal tentacles inflected.

Veratritie, Colchicinc, Theine. — Solutions were made of these three alkaloids by adding one part to 437 of water. Half-minims were placed, in each case, on the discs of at least six leaves, but no inflection was caused, except perhaps a very slight amount by the theine. Half-minims of a strong infusion of tea like- wise produced, as formerly stated, no effect. I also tried similar drops of an infusion of one part of the extract of colchicum, sold by druggists, to 218 of water : and the leaves were observed for 48 hrs., without any effect being produced. The seven leaves on which drops of veratrine had been left for 26 hrs. were given bits of meat, and after 21 hrs. were well inflected. These three alkaloids are therefore quite innocuous.

Curare. — One part of this famous poison was added to 218 of water, and three leaves were immersed in ninety minims of the filtered solution. In 3 hrs. 30 rn. some of the tentacles were a little inflected ; as was the blade of one, after 4 hrs. After 7 hrs. the glands were wonderfully blackened, showing that matter of some kind had been absorbed. In 9 lirs. two of the loaves had most of their tentacles sub-inflected, but the inflec- tion did not increase in the course of 24 hrs. One of these leaves, after being immersed for 9 hrs. in the solution, was placed in water, and by next morning had largely re-expanded

the other two, after their immersion for 24 hrs., were likewise placed in water, and in 24 hrs. were considerably re-expanded, though their glands were as black as ever. Half-minims were placed on the discs of six leaves, and no inflection ensued ; tut after three days the glands on the discs appeared rather dry, yet to my surprise were not blackened. On another occasion drops were placed on the discs of six leaves, and a considerable amount of inflection was soon caused ; but as I had not filtered the solution, floating particles may have acted on the glands. After 24 hrs. bits of meat were placed on the discs of three of these leaves, and next day they became strongly inflected. As I at first thought that the poison might not have been dissolved in pure water, one grain was added to 437 grains of a mixture of one part of alcohol to seven of water, and half-minims were placed on the discs of six leaves. These were not at all affected, and when after a day bits of meat were given them, they were slightly inflected in 5 hrs., and closely after 24 hrs. It follows from these several facts that a solution of curare induces a very moderate degree of inflection, and this may perhaps be due to the presence of a minute quantity of albumen. It certainly is not poisonous. The protoplasm in one of the leaves, which had been immersed for 24 hrs., and which had become slightly in- flected, had undergone a very slight amount of aggregation — not more than often ensues from an immersion of this length of time in water.

Acetate of Morphia. — I tried a great number of experiments with this substance, but with no certain result. A considerable number of leaves were immersed from between 2 hrs. and 6 hrs. in a solution of one part to 218 of water, and did not become inflected. Nor were they poisoned ; for when they were washed and placed in weak solutions of phosphate and carbonate of ammonia, they soon became strongly inflected, with the pro- toplasm in the cells well aggregated. If, however, whilst the leaves were immersed in the morphia, phosphate of am- monia was added, inflection did not rapidly ensue. Minute drops of the solution were applied in the usual manner to the secretion round between thirty and forty glands; and when, after an interval of 6 m., bits of meat, a little saliva, or particles of glass, were placed on them, the movement of the tentacles was greatly retarded. But on other occasions no such retar- dation occurred. Drops of water similarly applied never ha~ve any retarding power. Minute drops of a solution of sugar of the same strength (one part to 218 of water) sometimes retarded the subsequent action of meat and of particles of glass, and

sometimes did not do so. At one time I felt convinced that morphia acted as a narcotic on Drosera, but after having found in what a singular manner immersion in certain non-poisonous salts and acids prevents the subsequent action of phosphate of ammonia, whereas other solutions have no such power, my first conviction seems very doubtful. Extract of Hyoscynmus. — Several leaves were placed, each in thirty minims of an infusion of 3 grs. of the extract sold by druggists to 1 oz. of water. One of them, after being immersed for 5 hrs. 15 m., was not inflected, and was then put into a solution (1 gr. to 1 oz.) of carbonate of ammonia ; after 2 hrs. 40 m. it was found considerably inflected, and the glands much blackened. Four of the leaves, after being immersed for 2 hrs. 14 m., were placed in 120 minims of a solution (1 gr. to 20 oz.) of phosphate of ammonia; they had already become slightly inflected from the hyoscyamus, probably owing to the presence of some albuminous matter, as formerly explained, but the inflection immediately increased, and after 1 hr. was strongly pronounced ; so that hyoscyamus does not act as a narcotic or poison.

Poison from the Fang of a Living Adder. — Minute drops were placed on the glands of many tentacles; these were quickly inflected, just as if saliva had been given them. Next morning, after 17 hrs. 30 m., all were beginning to re-expand, and they appeared uninjured. Poison from the Cobra. — Dr. Fayrer, well known from his investigations on the poison of this deadly snake, was so kind as to give me some in a dried state. It is an albuminous substance, and is believed to replace the ptyaline of saliva. * A minute drop (about -^ of a minim) of a solution of one part to 437 of water was applied to the secretion round four glands ; so that each received only about 38i00 of a grain ('0016 nig.). Tho operation was repeated on four other glands; and in 15 m. several of the eight tentacles became well inflected, and all of them in 2 hrs. Next morning, after 24 hrs., they were still inflected, and the glands of a very pale pink colour. After an additional 24 hrs. they were nearly re-expanded, and completely so on the succeeding day; but most of the glands remained almost white.

Half-minims of the same solution were placed on the discs ol three leaves, so that each received rL_ Of a grain ('0675 mg.) ; in 4 hrs. 15 m. the outer tentacles were much inflected ; and after 6 hrs. 30 m. those on two of the leaves were closely inflected and the blade of one ; the third leaf was only moderately affected* The leaves remained in the same state during the next day, but after 48 hrs. re-expanded. Three leaves were now immersed, each in thirty minims of the solution, so that each received -^ of a grain, or 4'048 mg. In 6 in. there was some inflection, which steadily increased, so that after 2 hrs. 30 m. all three leaves were closely inflected; the glands were at first somewhat darkened, then rendered pale ; and the protoplasm within the cells of the tentacles was partially aggregated. The little masses of protoplasm were examined after 3 hrs., and again after 7 hrs., and on no other occasion have I seen them undergoing such rapid changes of form. After 8 hrs. 30 m. the glands had become quite white ; they had not secreted any great quantity of mucus. The leaves were now placed in water, and after 40 hrs. re-expanded, showing that they were not much or at all injured. During their immersion in water the protoplasm within the cells of the tentacles was occasionally examined, and always found in strong movement.

Two leaves were next immersed, each in thirty minims of a much stronger solution, of one part to 109 of water ; so that each received A of a grain, or 16'2 nig. After 1 hr. 45 m. the sub- marginal tentacles were strongly inflected, with the glands some- what pale ; after 3 hrs. 30 m. both leaves had all their tentacles closely inflected and the glands white. Hence the weaker solution, as in so many other cases, induced more rapid inflec- tion than the stronger one ; but the glands were sooner rendered white by the latter. After an immersion of 24 hrs. some of the tentacles were examined, and the protoplasm, still of a fine purple colour, was found aggregated into chains of small globular masses. These changed their shapes with remarkable quickness. After an immersion of 48 hrs. they were again examined, and their movements were so plain that they could easily be seen under a weak power. The leaves were now placed in water, and after 24 hrs. (i.e. 72 hrs. from their first immersion) the little masses of protoplasm, which had become of a dingy purple, were still in strong movement, changing their shapes, coalescing, and again separating.

In 8 hrs. after these two leaves had been placed in water (i.e. in 56 hrs. after their immersion in the solution) they began to re-expand, and by the next morning were more expanded. After an additional day (i.e. on the fourth day after their immer- sion in the solution) they were largely, but not quite fully expanded. The tentacles were now examined, and the aggregated masses were almost wholly redissolved ; the cells being filled with <4iomogeneous purple fluid, with the exception here and there of a single globular mass. We thus see how completely the proto- plasm had escaped all injury from the poison. As the glands were soon rendered quite white, it occurred to me that their texture might have been modified in such a manner as to prevent the poison passing into the cells beneath, and conse- quently that the protoplasm within these cells had not been at all affected. Accordingly I placed another leaf, which had been immersed for 48 hrs. in the poison and afterwards for 24 hrs. in water, in a little solution of one part of carbonate of ammonia to 218 of water ; in 30 m. the protoplasm in the cells beneath the glands became darker, and in the course of 24 hrs. the tentacles were filled down to their bases with dark-coloured spherical masses. Hence the glands had not lost their power of absorption, as far as the carbonate of ammonia is concerned.

From these facts it is manifest that the poison of the cobra, though so deadly to animals, is not at all poisonous to Drosera ; yet it causes strong and rapid inflection of the tentacles, and soon discharges all colour from the glands. It seems even to act as a stimulant to the protoplasm, for after considerable expe- rience in observing the movements of this substance in Drosera, I have never seen it on any other occasion in so active a state. I was therefore anxious to learn how this poison affected animal protoplasm ; and Dr. Fayrer was so kind as to make some obser- vations for me, which he has since published.* Ciliated epi- thelium from the mouth of a frog was placed in a solution of •03 gramme to 4-6 cubic cm. of water ; others being placed at the same time in pure water for comparison. The move- ments of the cilia in the solution seemed at first increased, but soon languished, and after between 15 and 20 minutes ceased ; whilst those in the water were still acting vigorously. The white corpuscles of the blood of a frog, and the cilia on two infusorial animals, a Paramsecium and Volvox, were similarly affected by the poison. Dr. Fayrer also found that the muscle of a frog lost its irritability after an immersion of 20 m. in the solution, not then responding to a strong electrical current. On the other hand, the movements of the cilia on the mantle of an Unio were not always arrested, even when left for a consider-

.ible time in a very strong solution. On the whole, it seema that the poison of the cobra acts far more injuriously on the protoplasm of the higher animals than on that of Drosera. There is one other point which may be noticed. I have occa- sionally observed that the drops of secretion round the glands were rendered somewhat turbid by certain solutions, and more especially by some acids, a film being formed on the surfaces of the drops ; biit I never saw this effect produced in so con- spicuous a manner as by the cobra poison. When the stronger solution was employed, the drops appeared in 10 m. like little white rounded clouds. After 48 hrs. the secretion was changed into threads and sheets of a membranous substance, including minute granules of various sizes.