Chapter X — 155 — Drosera 



From studies during the past three summers I can confirm Homes in 

 his claim that resting glands, that is glands found on young vigorous 

 resting leaves, can be found in a resting condition, meaning with cells 

 having a single grand vacuole, or with its cells in a condition which is 

 distinctly otherwise, that is, with an appearance which may be in- 

 terpreted as a mass of smaller irregular vacuoles, or as a network, prob- 

 ably fairly represented by Homes' fig. 60-63, 1932- Guided by what 

 we have seen in the tentacle cells, in which it seems reasonably certain 

 that the vermiform condition can give rise by confluence to a network, 

 temporary though it may be, we may agree that the same occurs in 

 the gland cells, as Homes believes, and he may be quite right. 



I have seen evidence, however, that, during the period after feed- 

 ing (with raw and purified egg albumin, pepsin, peptone Witte, 

 saliva) while aggregation follows in the tentacle cells, meaning specifi- 

 cally the breaking up of the grand vacuole into smaller ones, these be- 

 coming numerous, slender, actively agitated vermiform bodies of high 

 refringence (as so well depicted by Akerman), to suffer at length con- 

 fluence and total reversion, this series of changes is not followed in the 

 cells of both glandular courses, though some approach to it may be 

 observed in the lateral epidermal cells seen en face, and in the apical 

 cells of a gland which were distinctly not in the grand vacuolar state, 

 having instead a number of smaller irregular vacuoles, in appearance 

 at any rate. 



Lateral cells viewed en face present a crenated outline in conformity 

 with the buttresses which cut up the periphery of the cell into bays, 

 seen by Franca in Drosophyllum. I observed that in these cells, in 

 saliva, a droplet containing pigment would be formed in each bay, 

 there being as many droplets as bays. Dufrenoy's drawings indicate 

 that he saw the same condition, which he called aggregation, but ap- 

 parently did not connect the early form of the vacuole with the cre- 

 nated walls. These droplets formed in the bays might remain as such 

 or might run together to form a single drop containing all the pigment 

 of the cell, depending apparently on the size of the droplets and the 

 vigor of the process. In the apical cells, also in saliva, the whole mass 

 of vacuoles, whatever may have been their exact state, became con- 

 fluent and there was formed a single large drop, corresponding to 

 Homes' condensed vacuole. Here then we have a case which appears 

 to conform with Homes' observations. On the other hand, when the 

 gland cells are, to begin with, in the dilute vacuolar state, each having a 

 single grand vacuole (Homes' "vacuole diluee") when treated with 

 egg albumin, raw or purified, the first sign of response is to be seen in 

 ten minutes in the cells of the internal course in the lateral region of 

 the gland. The change advances toward its apex. In 90 minutes simi- 

 lar droplets appear in the epidermis lateral cells low down near the 

 base of the gland, again advancing toward the apex. These droplets 

 do not apparently appear in the grand vacuole but in the cytoplasm, 

 but this is a point very difficult to make out. In the course of time 

 the confluence of droplets yields a single large drop. This seems to be 

 what Darwin saw: " In 15 min. I distinctly saw extremely minute 

 spheres of protoplasm aggregating themselves in the purple fluid; these 

 rapidly increased in size, both within the cells of glands and of the 



