Francis E. Lloyd —HO— Carnivorous Plants 



equally glandular with the leaf, and since the life of a peduncle is fully 

 a month or more, whatever benefit may be derived from prey caught 

 by leaves may also be said to accrue from that caught by the peduncles. 



Cytological changes. — Darwin examined the condition of the glan- 

 dular cells after being in contact for some time with sources of matter 

 which was plainly absorbed, and found evidence of change in structure 

 and appearance of the protoplasm and its content, usually in the ap- 

 pearance of granular matter colored brownish, or in the cell contents, 

 at first limpid, being aggregated into slowly moving masses of proto- 

 plasm. The difficulties of observation and inference are obviously 

 great, a great deal more so than in the case of Drosera. Darwin re- 

 ferred the appearances to the absorption of food materials. 



NicoLOSi-RoNCATi (1912) endeavored to relate cytoplasmic changes 

 observed in fixed and stained material to secretive activity, in P. 

 hirtifiora. In actively secreting glands (mucilage glands presumably), 

 the cytoplasm is vacuolated and contains many fuchsinophile granules 

 scattered toward the periphery of the cell with moniliform bodies in 

 the vicinity of the nucleus. The nucleolus, large and intensely fuch- 

 sinophile at the beginning of secretion, diminishes notably in volume 

 and in capacity for staining in evidently secreting cells. The author 

 concluded that the first impulse to secretion comes from the nucleolus, 

 the primary granules of secretion being formed by the chromatin. 

 These diffuse throughout the body of the cell definitively elaborating 

 secretory substance. This work, while affording a beginning, does not 

 lead us very definitely forward, as at this time we are unable to dis- 

 tinguish the kind of secretion dealt with, whether of mucilage or en- 

 zymes. 



TiscHUTKiN (1889) carried out experiments similar to those of 

 Darwin, and worked also with glycerin extracts of leaves and mix- 

 tures of leaf secretion, withdrawn by means of a pipette, with glycerin, 

 acidified variously (HCl, formic, mahc acids). Both glycerin extracts 

 and mixtures gave only negative results. Albumen, gelatin and 

 fibrin placed on the leaves gave results for him much the same as for 

 Darwin. Tischutkin states then that in Pinguicula insects which 

 are caught call forth a secretion of acid sap which can procure a cer- 

 tain alteration of their substance. Examining the work of Rees, 

 Gorup and Will (later substantiated) he sees in its deficiencies ev- 

 idence of bacterial action and he comes to the conviction that the role 

 of the plant is the secretion of a medium which is suited to the hfe 

 and activity of microorganisms (bacteria), and concludes without fur- 

 ther experimental evidence that in Pinguicula we are deaHng with 

 bacterial action, in this agreeing with Morren (1875). 



Somewhat later Goebel also attacked the problem of digestion in 

 Pinguicula. When he put particles of fibrin on the leaves, the secre- 

 tion was intensified, and the smallest particles digested in 24 hours. 

 The secretion was weakly acid. When insects (those, as already said, 

 are always small, for Pinguicula is adapted to the capture and di- 

 gestion of only small ones) are found in an advanced stage of digestion, 

 the glands are found to contain droplets of fat. Large insects or fibrin 

 fragments are overcome by decay. By ad hoc culture experiments 

 Goebel showed that Tischutkin's views are not justified. He showed 



