42 PEOCEEDINGS OF THE 



ABSTEACTS. 



jS'ovember 20th, 1902. 



The President reminded the Society that exactly a year ago he 

 had the honour of giving an accomit of some observations upon 

 the action of the enzyme contained in the secretion of Xepenthes. 

 That enzyme, he then explained, not only possesses the property 

 of peptonising the higher proteids (e. g. fibrin), but is also pi'O- 

 teolytic, decomposing the proteid molecule into non-proteid nitro- 

 genous substances such as leucin and tryptophane. The proof of 

 this is afforded by the fact that liquids containing proteids that 

 have undergone digestion give the tryptophane-reaction ; that is, 

 a pink or A'iolet colour on the addition of chlorine-water. 



Since that time many other plants have been investigated with 

 the object of ascertaining (1) whether or not a digestive enzyme 

 were present, and (2) of determining the nature of its action. 

 In almost all cases the presence of a proteolytic enzyme has been 

 demonstrated. In the first instance plants which were knowR to 

 possess a peptonising enzyme were made the subject of experiment, 

 with the result that the enzyme was in all cases found to be 

 proteolytic. This is true of the juice of the Pineapple {Ananas 

 sativus. Schult. f.), of the latex of the Papaw (Carica Papaya, L.), 

 of the Pig (Ficus Carica, L.), of the milk of the Coco-nut (Cocos 

 nucifera, L.), of the seeds of Vicia Faba, L., and of Hordeum 

 vidgare, L., of Teast {Saccliaromyces Cerevisice, Meyen), and of the 

 Bacteria of putrefaction (see 'Annals of Botany,' vol. xvi. 1902, p. 1). 



The investigation \\as then extended to different parts of widely 

 differing plants. In view of the fact that the pi-oteids occurring 

 uatHrally in plants are such (e. g. globulins and albumoses) as are 

 readily digested, whereas those genernlly used (e. g. egg-albumin, 

 fibrin) are much more resistant, the material to be digested was 

 supplied in the form of the commercial product known as "Witte- 

 peptoue, a mixture of albumoses and peptones. It \vas found 

 that, with few exceptions, an enzyme was present which, as proved 

 by the tryptophane-reaction, proteolysed these substances in 4-20 

 hours. Only those experiments are relied on in which the period 

 of digestion was too brief to admit of putrefaction ; or in which 

 an antiseptic (H C N, or chloroform -water) was employed. The 

 digestive power is destroyed by boiling. 



The plants and parts of plants investigated are the following : — 



Fniifs: Melon; Cucumber; Tomato : Vegetable Marrow ; Black 

 and White hothouse Grapes ; Pear (Beurre Hardi) ; the 

 Orange, where the peel, but not the juice, was found to 

 digest ; Banana. 



Lacticiferous plants : Eu/pliorhia Cliaracias (shoots) ; leaves of 

 the Lettuce. 



Seeds : Green Peas : Wheat-Germ. 



Stems: Vegetable Marrow ; BaJdia variabilis ; Mirabilis Jalapa; 

 Heliantlius tuberosiis. 



