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Physiology and the whole organism  ·  Article

Aggregation of protoplasm in Drosera tentacle cells

Aggregation of protoplasm is the clumping of the cell contents of a plant into discrete masses after stimulation. Darwin gave it a long chapter in Insectivorous Plants (1875), concerning gland and tentacle cells.1 He treated it as a visible response of living matter, with its own causes, movements and reversal.23

Earliest held
1875, Darwin, C.
Most discussed in
Insectivorous Plants, 1875
In the library
120 passages in 5 works
Rewritten
2026-11-06
18501875190019251950197520002025Darwin, C., 18751Darwin, C., 18752Darwin, C., 18753Darwin, C., 18804Darwin, C., 18805Child, C. M., 19156Bayliss, W. M., 19157Meyer B, Ansorge C, Nakagaki T, 20178
01

Darwin's chapter outline

The chapter opens with the nature of the cell contents before aggregation and the various causes that excite it. It states that the process commences within the glands and travels down the tentacles.1 Later headings cover the aggregated masses and their spontaneous movements, and currents of protoplasm along the cell walls.2 What the list shows is the order of his inquiry: the resting state, the triggers, the spread, then the movements.12

02

Ammonia and other agents

The headings name carbonate of ammonia as a main agent. They say that granules in the protoplasm flowing along the walls coalesce with the central masses.2 They also record the minuteness of the quantity of carbonate of ammonia that causes aggregation. Other ammonia salts, other substances, organic fluids, water and heat are listed in turn.2 The list ends with redissolution of the masses and the proximate causes of aggregation, followed by a summary and supplementary observations on roots.3 In The Power of Movement in Plants (1880), Darwin applied the same test to other tissue. Hairs on clover calyces were placed in a weak ammonia solution. Their contents became aggregated and then showed the usual slow movements.4

03

Ammonia on whole leaves

The 1880 work also records ammonia acting on a whole leaf. A drop of carbonate of ammonia solution was placed on the disc of a leaf. Darwin reported that it blackened the glands and induced inflection of many tentacles.5 The leaf was followed afterwards. By the end, the tentacles had re-expanded and the glands had recovered their proper colour.5

04

Later uses of the term

Later authors use aggregation in related senses. Child (1915) asked whether a particular aggregation of protoplasmic substance is an individual or merely an aggregation, and called this sometimes difficult to settle.6 Bayliss (1915) discussed whether stainable bodies in nerve cells were present as aggregated masses or diffused. He judged the diffuse view more probable and cited Mott and Marinesco, who saw no such bodies in living cells.7 Meyer, Ansorge and Nakagaki (2017) describe the slime mold plasmodium as an aggregate of protoplasm with a gel phase forming tube walls and a sol phase flowing within.8

SourcesEach quotation was checked word for word against the passage it opens.
  1. Nature of the contents of the cells before aggregation — Various causes which excite aggregation — The process commences within the glands and travels down the tentaclesDarwin, C., 1875 · Insectivorous Plants · open at passage 1
  2. Currents of protoplasm along the walls of the cells — Action of carbonate of ammonia — The granules in the protoplasm which flows along the walls coalesce with the central massesDarwin, C., 1875 · Insectivorous Plants · open at passage 80
  3. Redissolution of the aggregated masses — Proximate causes of the aggregation of the protoplasm — Summary and concluding remarks — Supplementary observations on aggregation in the roots of plants.Darwin, C., 1875 · Insectivorous Plants · open at passage 80
  4. their proto- plasmic contents immediately became aggregated and afterwarda displayed the usual slow movements.Darwin, C., 1880 · The Power of Movement in Plants · open at passage 1010
  5. a drop of a solution of carbonate of ammonia (2 gr. to 1 oz. of water) was placed on the disc, and this blackened the glands and in- duced inflection of many of the tentacles.Darwin, C., 1880 · The Power of Movement in Plants · open at passage 474
  6. it is sometimes difficult to determine whether a particular aggregation of protoplasmic substance is an individual in the biological sense or merely an aggregation.Child, C. M., 1915 · Individuality in Organisms · open at passage 15
  7. Mott (1912) and Marinesco (1912, see page 470 below), in fact, have shown, by observations on living nerve cells under dark ground illumination, that there are neither Nissl bodies nor neurofibrils in the living state.Bayliss, W. M., 1915 · Principles of General Physiology · open at passage 76
  8. The protoplasm is differentiated into two phases: a gel phase (ectoplasm) that makes up the walls of the tubular structures, and a sol phase (endoplasm) that flows within the tubes.Meyer B, Ansorge C, Nakagaki T, 2017 · The role of noise in self-organized decision making by the true slime mold… · open at passage 8
Linked ideas
Covers the same plant and its glands, whose response to ammonia and other agents is where Darwin observed aggregation.
Tentacle inflection followed the same ammonia treatments that Darwin linked to aggregation in the cells.
Heat and chemical agents appear in both this chapter's headings and Darwin's wider study of plant excitation.
The slime mold plasmodium, an aggregate of protoplasm with flowing sol, shows organised behaviour without nerves.
Child's question of when an aggregation of protoplasm counts as an individual bears on the unit of self.
Circumnutationrelated to
Darwin's 1880 work records leaf circumnutation alongside the ammonia response in Drosera.
Where it is discussedPassages matching aggregation of protoplasm, aggregated masses, currents of protoplasm along the walls, carbonate of ammonia
1875Insectivorous Plants · Darwin, C.114
1880The Power of Movement in Plants · Darwin, C.3
2017The role of noise in self-organized decision making by the true slime mold… · Meyer B, Ansorge C, Nakagaki T1
1915Individuality in Organisms · Child, C. M.1
1915Principles of General Physiology · Bayliss, W. M.1