The Dynamics of Living Matter

better the transformation which thus occurs in these branches, it may be stated that under normal conditions they have a limited growth (see Fig. 60), are directed upward, and have polyps on their upper side * Loeb, Untersuchungen zur physiologische Morphologic der Thiere, II, 1891. (Fig. 60). The parts which grow down (Fig. 59) have no polyps, but at- tach themselves like true roots to solid bodies. Thus the changed posi- tion of the stem alone, without any operation, suffices to transform the lateral branches, whose growth is limited, into roots with unlimited growth. The lateral branches on the upper side of the stem do not undergo such a transformation except in the immediate surroundings of the place where a new stem arises. It seems that the formation of a new stem also causes an excessive growth of roots, possibly because the formation of new branches causes the removal of substances which naturally inhibit the formation of roots. If a piece from the stem be put vertically into the water with top downward, the upper- most point may continue to grow as a stem, while the lowest point may give rise to roots. In this case, therefore, a change in the orientation of organs has the effect of changing the character of organs.

We have already mentioned the fact that in Eudendrium the formation or regeneration of polyps is only possible in the light. In many hydroids, contact with solid bodies seems to favor the formation of stolons, although such contact is not the only condition that brings about this result. Fig- ure 6 1 shows a piece of a stem of Pennaria, a hydroid, which was lying on the bottom of an FIG. 61. stolons at both ends. In Margelis, another hydroid, I observed that, without any operation, the apical ends of the branches which were in contact with solid bodies continued to grow as roots, while those surrounded by sea water continued to grow as stems.

In all the cases mentioned thus far one point has not yet been dis- cussed ; namely, where the material of which the new organs consist comes from. In the case of plants, where the green leaves assimilate, and the salts are taken up from the soil or water, this source is evident, as it is also in the case of the animals which take up food; but in the case of a piece from the body wall of an Actinian which has no digestive organs, the material of the new tentacle can come only from one of two sources, viz. from the chlorophyll (or parasitic algoe?) which are con- tained in the ectoderm, or through a hydrolysis of material contained in the cells of the Actinian itself ; this latter case would be comparable to Miescher's observation of the growth of the sexual glands at the expense of muscular tissue. In the case of the polyp formation in Tubularia, the transformation of the material of the stem into the polyp can be directly observed (Bickford, Driesch, and others). It is even doubtful in these cases whether a hydrolysis is necessary in any considerable amount, and it looks as if the tissues could be utilized directly for the formation of the polyp ; some hydrolysis may however occur. In the above-men- tioned case of the transformation of a branch of Antennularia into a root, the polyps that were on that branch first disappear. I cannot make any definite statement as regards their fate, but it is not impossible that the material of the polyps is used for the formation of the new roots. I have observed more closely the transformation of an organ into more undifferentiated material in Campanularia, Fig. 62, a hydroid.* This organism shows a remarkable stereo- tropism. Its stolons attach themselves to solid bodies, and the stems appear on the side of the stolon exactly opposite the point or area of con- tact with the solid body. The stems grow, moreover, ex- actly at right angles to the solid surface element to which the stolon is attached. If such a stem be cut and put into a watch glass with sea

water, it can be observed that those polyps which do not fall off go through a series of changes ,which make it appear as if the differ- entiated material of the polyp were transformed into undifferentiated material. The tentacles are first put together like the hairs of a camel's-hair brush (Fig. 63), and gradually the whole fuses to a more or less shapeless mass which flows back into the periderm, Fig. 64. It follows from this that in this process certain solid constituents of the polyp, e.g. the cell walls, must be liquefied. I pointed out the analogy of these phenomena with Miescher's observations in the salmon. This un- differentiated material formed from the polyp may afterward flow out again, giving rise to a stem or a polyp ; to the former where it comes in contact with a solid body, to the latter where it is surrounded by sea

water. This observation seems to indicate the possibility that the pro- cesses of organization are reversible, in some cases at least. Giard and Caullery have found that a regressive metamorphosis occurs in Synascidians, and that the animals hibernate in this condition. The muscles of the gills of these animals are decomposed in their indi- vidual cells. The result is the formation of a parenchyma which con- sists of single cells and of cell aggregates resembling a morula.*

Driesch found that when he isolated Clavellina that part of the ani- mal containing the gills underwent a retrogressive transformation simi- lar to that observed by Giard and Caullery, and that afterward these masses gave rise to a new Ascidian.f The phenomena observed by Giard and Caullery, as well as the experiments of Driesch, resemble those in Campanularia, and Driesch also expresses the opinion that this is a case of reversibility of the processes of development.

The idea that the process of development is in certain forms reversi- ble is also supported by the experiments of Frank Lillie on fresh-water Planarians. Lillie found that adult fresh- water Planarians if exposed to starvation not only become gradually smaller in size but ultimately return to an embryonic form ! These experiments have been repeated and confirmed by Schultze. There is a possibility that a definite kind of chemical substances must be present in order to make development, regeneration, and growth possible. Such tissues as contain these substances (or mixture of substances) may be called embryonic. If this idea be correct, and if it be true that phenomena of development are reversible, — to a great extent in a few forms, and to some extent perhaps generally, --the question might be raised whether or not one of the conditions of regeneration is the transformation of adult tissue into more embryonic tissue. If this were true, the power of regeneration of an organism might depend upon the degree of reversibility of the processes of development in such a form. It is certainly in harmony with such an idea that forms like Hydroids, Ascidians, and fresh-water Planarians, where the reversibility of the process of development is most outspoken, possess also the greatest power of regeneration among animals. The idea suggested is further supported by the fact that the power of regeneration by the embryo is often considerably greater than the power of regeneration of the same form in the adult stage. The tadpole of a frog is capable of regenerat- ing a leg, while this is impossible in the adult frog.

This removes the contradictions into which we fall if we try to rep- resent the power of regeneration as parallel to the position of an animal in the natural system. We find Annelids, such as the leech, whose power of regeneration is decidedly less than that of some vertebrates, e.g. the salamander. If we cut off the tail of the salamander, a complete regen- eration of this organ with all its parts, bones as well as spinal cord, occurs. If we cut off a number of segments from a leech, the wound is

covered with epidermis and thus heals, but no regeneration of the lost segment occurs. I have kept headless pieces of a leech alive for almost a year, without any trace of a regeneration occurring. We thus see that an Annelid may possess a much lower power of regeneration than a vertebrate. It has been maintained that the power of regeneration is due to natural selection, and, therefore, runs parallel to the liability of an ani- mal to injury. I do not believe that such ideas are of more value in biology than they are in physics or chemistry. It is not very obvious either why "nature" should care so much more to preserve the tail of a salamander than the foot of the leech. Morgan has treated this sub- ject exhaustively, and I refer the reader to his writings.*

BIOLOGISTS are confronted with two problems of transformation; namely, the artificial transformation of dead into living matter, and the artificial transformation of one species of plants or animals into another. Will it be possible to solve these problems? It is certain that nobody has thus far observed the transformation of dead into living matter, and for this reason we cannot form a definite plan for the solution of this problem of transformation. But we see that plants and animals dur- ing their growth continually transform dead into living matter, and that the chemical processes in living matter do not differ in principle from those in dead matter. There is, therefore, no reason to predict that abiogenesis is impossible, and I believe that it can only help science if the younger investigators realize that experimental abiogenesis is the goal of biology. On the other hand, our lectures show clearly that we can only consider the problem of abiogenesis solved when the artificially produced substance is capable of development, growth, and reproduc- tion. It is not sufficient for this purpose to make proteins synthetically, or to produce in gelatine or other colloidal material round granules which have an external resemblance to living cells.

In this connection another problem may be mentioned; namely, whether there exists a natural death or, in other words, whether death is the necessary outcome of development, and whether rejuvenation and the beginning of a new cycle of life are impossible. In man and higher mammalians death seems to be caused directly or indirectly through microorganisms or other injuries to vital organs. The example of cer- tain plants, e.g. the Sequoia in California, shows that certain organisms may live thousands of years.

I pointed out a few years ago that the egg is a valuable object for the study of this problem. The process of fertilization of the egg is a life-saving act. The mature egg which is not fertilized dies as a rule very quickly under conditions under which the immature or the fertilized egg remains alive. If, e.g., fertilized and unfertilized eggs of the same female of Fundulus (a marine fish) are kept in the same vessel with sea water or distilled water, the fertilized eggs remain all alive and develop, while the unfertilized eggs die in a few hours and become putrid in a

day or two. The case of starfish eggs is possibly still more striking. The egg of a starfish, Asterias Forbesii, is, as a rule, immature when taken from the ovary, and maturates when put into sea water. Very often not all the eggs of a female undergo maturation in sea water, and I have found that maturation can be inhibited by putting the eggs into slightly acid sea water. It was found that the eggs which maturate but are not caused to develop die in a few hours, while the eggs that are caused to develop or the eggs which fail to maturate (or are prevented from so doing) will not die, even if kept in the same dish of sea-water.* The eggs which are allowed to maturate, but are not caused to develop, die just as well in perfectly sterilized sea water, in which the eggs keep free from putrefaction for months, as in normal sea water or in sea water to which cultures of bacteria of putrefaction have been added. These and other facts indicate that in the mature egg processes occur which lead invariably to the death of the egg under circumstances under which the fertilized egg invariably keeps alive.

As far as the second problem of transformation is concerned, namely, the transformation at desire of one species into another, conditions are more favorable since De Vries has succeeded in actually observing the transformation of one species into another. De Vries discovered in experiments which have been carried on since 1886 in the most painstaking and laborious way, that from the seeds of a certain plant, (Enothera Lamarckiana, there arise always a very small number of plants which differ from the mother plants in definite characteristics.! "These plants are from the very first true to seed!" De Vries thus discovered that new forms arise from (Enothera La- marckiana, not by gradual variation, as Darwin and Wallace had as- sumed, but by a sudden jump. As an instance, the origin of the species (Enothera gigas from (Enothera Lamarckiana may be mentioned. It originated in De Vries's culture of 1895 in a single specimen, and this first specimen was, as soon as it flowered, fertilized with its own pollen. The action of insects was absolutely excluded. The following spring the pure seed was sown (1897). The several hundred plants which thus originated all differed in the same way from (Enothera Lamarcki- ana, resembling the mother plant of (Enothera gigas. The species has since remained constant. In the same sudden manner the other new species of (Enothera originated from (Enothera Lamarckiana. To this sudden, discontinuous form of evolution De Vries gave the term "muta- tion." The observations of De Vries also explain the fact which Dar- win's idea of gradual evolution failed to explain ; namely, that species can and usually do remain constant for thousands of years. The plants

found in Egyptian tombs do not differ from the species existing to-day. According to De Vries, a period of constancy may be followed by an explosive tendency to mutate, whereby new species arise suddenly, while the original species continues to exist. The most important fact, however, from our point of view is the per- fect harmony between De Vries's theory of mutation and Mendel's ex- periments on hybridization. The latter lead to the idea that hereditary characteristics are transmitted by specific determinants in the sexual cells, and that each characteristic must be represented by such a deter- minant in the sexual cells. No two forms can have a closer resemblance than corresponds to the difference between two determinants. If the latter are comparable to the members of a series of compounds, e.g. of alcohols, there is no more a transition possible between two species sepa- rated by a difference in only one determinant than there is a transition possible between the two neighboring alcohols of the same series. This means that evolution must be discontinuous, as De Vries has actually discovered it to be.

Not all the new species which originate from (Enothera Lamarckiana are capable of existence. The first mutation De Vries observed was a form having pollen unfit for fertilization. It goes without saying that such a form cannot exist in nature. But other forms can exist, and do propagate side by side with (Enothera Lamarckiana. The limitation for newly produced species is not the struggle for existence, but a faulty construction. The idea that mutation is working in a definite direction is a mere anthropomorphism, and like all anthropomorphisms is in contradiction with the facts.

imitation of movements of, 56. Amphipyra, stereotropism of, 157. Amphoteric character of proteins, 35. Anaesthetics, 6. Antagonistic effects of salts, 46. of salts with univalent cations and bivalent or trivalent cations, 47. Antennularia, geotropism of, 148. certain wave lengths, 115. Associative memory. 6. Asterias, speedy death of unfertilized maturated eggs, 224. Astrospheres, orientation of, 65. Autoxidizable substances, 13. isolated, development of, 30. Blue rays most effective in heliotropism,

in phenomenon of contact reaction, 83. Calcium salts, in muscular contraction, 79. in coagulation of milk, 89. Campanularia, transformation of organs production in active nerve, 68. in cell division, 62. in lack of oxygen, in seeds, 22. in muscles in absence of oxygen, 23. through enzyme action, 21. Carroll, 27. Castle, 164, 186. Catalase, 27. Catalytic action, 8. of lipase, 9. of platinum-black, n. inhibited by poisons, 27. in respiration, 13. Catelectrotonus imitated through action

Chatopterus, artificial parthenogenesis produced by K-salts, 166, 174. Chemotropism, 152. biological significance of, 155. reaction of bacteria and Infusoria to Colloidal character of living matter, i. Colloidal solutions, 34. electrical charge of, 34. precipitation by salts, 36. relation to cell life, 37. amphoteric colloids, 35. Colloids, nature of, i, 33. disintegration by, 103. Contact irritability, produced by sub- stances which precipitate calcium, 83.

rhythmical contractions only in, 78. Elvove, 19. Embryos, from deformed eggs, 193. reversible action of, 9. Eudendrium, effect of light in organ for- mation, 115. produced by hydrocarbons, 169. formation of, antagonized by H-ion, biological effects, in. chemical effect, 106. coagulation of proteins, 107. coagulation of colloids a function of effect on coefficient of partition, m. poisons, activity of, influenced by, Heliotropic reactions, sense of, 130. reaction velocity in, 130. effect of differences of intensity of

chemical substances, 131. changes in intensity of heliotropism by chemical substances, 132. intensity of reaction at certain stages stages of development, 133. in larva? of Limulus, 133. effect of temperature on sense of reac- tion in Polygordius, and in Coppods, nauplii of Balanits, 134. Heliotropism, of sessile organisms, 117. green, blue, and violet end of spec- of free-moving organisms, 124. in larvae of Eudendrium, 125. in Aphides, 126. in caterpillars of PortheSia, 126. direction of motion determined by direction of light rays and not by intensity, 126. negative heliotropism in animals,

imitated by platinum-black, n. Liquefactions in absence of oxygen, Metabolism, different in presence and in lack of oxygen, 18. Ocneria, 190. (Enothera, 224. Oker-Elom, 69. Oligodynamic effects, 73. Ophelia, artificial parthenogenesis in, 175. Organisms as chemical machines, i. Orthoptera, spermatozoa of, 188. Osmotic pressure and exchange of liquids between the cells and surrounding liquids, 41. effect of certain poisons resembles effect of lack of oxygen, 21.

Parthenogenesis, natural, in Aphides, 165. in bees, 165. in starfish, 173. artificial, by raising concentration of Pigment granules in Tubularia, 205. Planarians, reactions to light, 136. Plants, nutritive solutions for, 71. Platinum-black, enzyme action of, n. Polarity in Tubularia, due to a current, 203. Polygordius, heliotropism in, 133. Poly orchis, effect of ions on, 87, 88, 91. Porthesia, heliotropism of, 126. Potassium, non-dissociable compounds

with protoplasm, 73. Prentiss, 152. Protective solutions, 77. Proteins, amphoteric character, 35. Proteolytic enzymes, general occurrence Psychology of lower forms, 158. Purgative effects of salts, inhibited by effect of green plants on, 98. Reaction velocity, effect of heat on, 108. Respiration as a catalytic process, 13. Reversible processes, in enzyme action, 9. Starvation, effect on Planarians, 221. Stereochemistry and enzyme action, 24. Stereotropism, 155 ff.

Discussions of Current Biological Problems. Modern Text and Reference Works. Adapted for General Reading, also for Advanced Courses in High Schools, I. The Anticipation and Interpretation of Nature. II. Among the Greeks. III. The Theologians and the Natural Philosophers. IV. The Evolutionists of the Eighteenth Century. V. From Lamarck to St. Hilaire. VI. Darwin. Index. " But whether the thread be broken or continuous, the history of thought upon this all-important subject is of the deepest interest, and Professor Osborn's work will be welcomed by all who take an intelligent inter- est in Evolution. Up to the present, the pre-Darwinian evolutionists have been for the most part considered singly, the claims of particular naturalists being urged often with too warm an enthusiasm. Professor Osborn has undertaken a more comprehensive work, and with well-balanced judgment assigns a place to each writer." — Professor EDWARD B. POI'LTON, in Xatiire, London.

By ARTHUR WILLEY, Sc.D., formerly Balfour Student of the University of Cambridge; Tutor in Zoology, Columbia University ; now Curator ot the Museum of Colombo, Ceylon. 316 pages ; 136 illustrations. Price $2.50, net. Contents. — Introduction. I. Anatomy of Amphioxus. II. Anatomy of Amphioxus (cotit.). III. De- velopment of Amphioxus. IV. The Ascidians. V. The Protochordata in their Relation to the Problem of Vertebrate Descent. " The observations on Amphioxus made before the second half of the present century, amongst which those of Johannes Miiller take a foremost place, showed that this remarkable animal bears certain resemblances to Vertebrates; and since then its interest in this respect has gradually become more apparent ... A con- secutive history of the more recent observations was, therefore, greatly needed by those whose opportunities did not permit them to follow out the matter for themselves, and who will welcome a book written in an extremely lucid style by a naturalist who can speak with authori y on the subject." — Professor W. NEWTON- PARKER, in Nature, London.

By BASHFORD DEAN, Ph.D., Professor of Vertebrate Zoology, Columbia University. 300 pages; 344 illustrations. Price $2.50, net. Contents. — I. Introductory. The form and movement of Fishes. Their classification ; geological dis- tribution ; mode of evolution. The survival of generalized forms II. The evolution of Structures char- acteristic of Fishes ; e.t>. (i) gills, (2) skin defences, teeth, (3) fins, and (4) sense organs III The Lampreys and their allies; their structures and probable relationships. The Ostracoderms and Palaeospondylus.

IV. The Sharks. Their plan of structure: prominent forms, living and extinct; their interrelationships. V. The Chimseroids. Their characteristic structures, their representatives and relationships VI. The Lung- fishes. Their structures ; extinct and recent forms ; the evolution of the group. VII. The Teleostomes (if. Ganoids and Teleosts) Typical members; their structures and interrelationships; their probable descent. VIII. The Groups of Fishes contrasted from the Standpoint of Embryology. Their eggs and breeding habits. Outlines of the development of Lamprey, Shark, Lung-fish, Ganoid, and Teleost. Their larval development. Derivation of Names. — Bibliography. — Explanatory Tables. — Index.

This work has been prepared to meet the need of the general student for a concise knowledge of the living and extinct Fishes. It covers the recent advances in the comparative anatomy, embryology, and palaeontology of the five larger groups of Lampreys, Sharks, Chimaeroids, Teleostomes, a.nd Dipnoans — the aim being to furnish a well-marked ground plan of Ichthyology. The figures are mainly original and designed to aid in practical work as well as to illustrate the contrasts in the development of the principal organs through the five groups.

" Dr. Bashford Dean is known to zoologists, first, as the author of exhaustive and critical articles in the publications of the United States Fish Commission, on the systems of oyster culture pursued in Europe; and, secondly, as an embryologist who has lately been doing good work on the development of various Ganoid fishes and the comparison that may be instituted with Teleostei. His recent addition to the well-known ' Columbia University Biological Series,' now being brought out by The Macmillan Company, under the editor- ship of Professor H. F. Osborn, is an interesting volume upon fishes, in which considerable prominence is given to the fossil forms, and the whole subject is presented to us from the point of view of the evolutionist. This is the characteristic feature of the book. From the very first page of the Introduction to the last page in the vol- ume, preceding the index, which is a table of the supposed descent of the groups of fishes, the book is full of the spirit and the language of evolution." — Professor W. A. HERDMAN, in Nature, London.