Francis E. Lloyd — 104 — Carnivorous Plants 



With neutral red the protoplasm displays a great number of small red 

 granules, considered to be granules of secretion. On the other hand 

 the deeper cells are filled with voluminous granulations of dark red 

 color. In this way it is supposed that the power of absorption is 

 demonstrated, for when prey has been captured, the superficial cells 

 show only the small granules, while the deeper cells and the distal 

 stalk cells are at the same time found crowded with grey or black 

 granules in addition to the secretory granules seen also in the outer cell 

 layer. The recounted facts are held to support Fran^a's conclusion 

 that the outer glandular layer of cells is secretory only and the inner 

 layer both secretory and absorptive. Additional and supporting evi- 

 dence is found by Franca in the presence of canalicuh. Some occur 

 "in the thickness" of the membranes between the cells of the two 

 layers and open on the outside of the gland by means of minute oval 

 mouths. It is these which permit the entrance of absorbed substances 

 to the deeper cell layer. Others occur in "the thickness" of the but- 

 tresses of the epidermal cells (between which fingers of the protoplasm 

 project, as described by Haberlandt for Drosera), and these "without 

 doubt" permit the escape of secretion. I have carefully examined 

 preparations after treatment with II2S04, followed by Sudan III and 

 have been unable to find any evidence of pores. The evidence in the 

 form of a drawing in his plate has httle convincing effect. 



A critical study of Drosophyllum was undertaken by Quintanilha 

 at Coimbra. His results, pubHshed in 1926, briefly stated are as fol- 

 lows. Drosophyllum is indeed a carnivorous plant, acting by means of 

 a proteolytic ferment of the type, of animal pepsin. A mosquito can 

 be completely digested in 24 hours. Bacterial digestion does not 

 enter into the picture (in this agreeing with Goebel, whose experi- 

 ments were repeated and verified). The stalked glands are essentially 

 organs of capture but at the same time they are "signales d'alarme"; 

 that is, on capture of an insect, they send a stimulus to the sessile 

 glands and provoke their activity. These are exclusively organs of di- 

 gestion and absorption, but they act only on stimulation. Experimen- 

 tally and under favorable conditions, the stalked glands may digest 

 very small amounts of albumen without the intervention of the sessile 

 glands, but the proteolytic properties of the mucilage are always in- 

 significant. Experimentally it was shown also that the sessile glands, 

 when previously excited, can digest and absorb albumen without the 

 intervention of the stalked glands which had been removed by ampu- 

 tation, and in this condition the absorption is as rapid, or even more 

 rapid, than it would be in collaboration with the stalked glands be- 

 cause of dilution of the secretion. In the normal state the stalked 

 glands act as traps and furnish stimuli to the sessile glands. 



Excitation of the sessile glands can be procured directly by chemi- 

 cal but not by mechanical means and indirectly by both means. Simple 

 pressure or friction of the stalked glands does not procure excitation 

 of the sessile. However, the cutting off of the glands from the stalks 

 can excite indirectly and mechanically the sessile glands. The ex- 

 citation is slow of transmission and is limited to an area of about i cm. 

 from the tentacle stimulated. On anatomical grounds Quintanilha 

 inclines to believe with Fenner that the phloem of the vascular system 



