PROTEIDS AS POISONS. 55 



foods. 1 Its action has been studied by Chittenden 2 and his pupils. It is a 

 ferment of intense activity, and acts well in neutral, acid, and alkaline 

 solutions, especially at 60 C. The ferment itself is associated or identical 

 with a proteose-like substance in the juice. The products of its action 

 (proteoses and peptone) are like those of other proteolytic ferments. 



I have alluded to these two ferments because they have formed the basis 

 of very thorough investigations, not because they are in any way exceptional 

 occurrences in the vegetable kingdom; as already stated, such ferments 

 probably play an important part in all plants, by converting the insoluble 

 proteid of the seed into the soluble nitrogenous substances of the sap. 3 



PROTEIDS AS POISONS. 



The line between food and poison is easily crossed. When, a few 

 years ago, the idea was first mooted that proteicls may act as poisons, it 

 was received with incredulity in many quarters ; but there can now be 

 no doubt that it is a fact. 4 



The best known of the vegetable proteid poisons are : 



1. Those contained in the seeds of jequirity (Abrus precatorius). 

 Warden and Waddell 5 named the poisonous substance abrin. S. Martin 6 

 separated the two proteicls a globulin and a proteose of which it is 

 composed. The material is used as a drug to produce conjunctivitis. 



2. The proteid associated with or identical with papain (S. Martin). 



3. Ricin, the poisonous proteid in castor-oil beans. 7 



4. Lupino-toxin from Lupinus luteus. 8 



The most important of the animal proteid poisons are 



1. Snake poison. 



2. Proteicls in the serum of certain fishes (conger eel, mursena, etc.). 9 



3. Proteid poisons found in certain spiders, 10 and in the stinging 

 apparatus of many insects. 



4. Ordinary peptones and proteoses ; 0'3 gr. of commercial peptone 

 per kilog. of body weight is in clogs usually fatal, when injected into 

 the blood. 



5. Nucleo - proteicls. These were called tissue fibrinogens by 

 Wooldridge, and cause intravascular clotting when injected into the 

 blood (see " Coagulation of Blood "). 



6. Poisonous proteicls produced by bacterial action. This subject 

 has recently received much attention, and opens up the whole subject 

 of toxins and antitoxins. To go into this matter thoroughly would 



1 Bull. Pharm., Detroit, 1891, vol. v. p. 77. 



2 Trans. Connect. Acad. Arts and *'c., New Haven, 1891, vol. viii. ; Journ. PhysioL, Cam- 

 bridge and London, vol. xv. p. 249. 



3 See further Green's papers already quoted ; also J. R. Green, " On the presence of 

 vegetable trypsin in the fruit of Cucumis utilis and other plants," Ann. agronomiqucs, 

 Paris, tomexix. p. 508 ; Neumeister, Ztschr. f. BioL, Mimchen, Bd. xxx. Another recent 

 paper on the subject (J. Hjort, Oentralbl. /. Physiol., Leipzig, 1896, Bd. x. S. 192) shows 

 that there are similar ferments in fungi. 



4 Nencki's opinion that poisonous proteids are more labile than other proteids can 

 hardly be considered an explanation of this fact (" Ueber die labile Eiweissstoffe, " Wchnschr. 

 f. Pharm., 1891, No. 29). 



5 "Non-Bacillar Nature of Abrus Poison," Calcutta, 1884. 



6 Brit. Med. Journ., London, 1889, vol. ii. p. 184. 



7 Stillmark, Pharm. (Jcntr.-ltt., Leipzig, 1890, Bd. xxx. S. 650. 

 * Schmidt's Jahrb., Leipzig, 1888, Bd. cciv. S. 10. 



9 Mosso, Jahrcsb. ii. d. Fortschr. d. Thier-Chem., Wiesbaden, Bd. xviii. S. 92. 

 10 Robert, Sitzungsb. d. Dorpatcr naturforsch. Gcsellsch., 1888 ; Centralbl. /. d. ined. 

 Wisscnsch., Berlin, 1888, S. 514. 



