2 SCIENCE PROGRESS. 



prepared in a pure condition it would be found to possess 

 no toxic properties. This hypothesis may be correct, for 

 the methods at present in vogue for obtaining pure proteids 

 leave much to be desired. These methods, however, im- 

 prove year by year ; but as they improve, the toxic power of 

 the poisonous members of the albuminous group does not 

 diminish, and it appears more and more certain that it is the 

 proteid itself which is the poisonous agent. 



Proteid poisons have been obtained from both the vege- 

 table and animal kingdoms. Thus among those obtained 

 from plants, one may mention the proteids obtained from 

 jequirity seeds, the proteid associated with or identical with 

 the ferment papain of the papaw plant, and lupino-toxin 

 from the yellow lupin. 



The most important of the animal proteid poisons are 

 snake poison ; the proteids in the serum of the conger eel 

 and other fish ; and proteid poisons found in certain 

 spiders. 



Poisonous proteids are also formed during ordinary di- 

 gestive processes in the alimentary canal of every one of us 

 from the proteids taken in as food. The peptones and the 

 proteoses or albumoses (intermediate products in the pro- 

 cess of hydration of which the terminal product is peptone) 

 are fairly powerful poisons. 0*3 gramme per kilogramme 

 of body weight injected into the blood will kill a dog, 

 producing a loss of coagulability of the blood, a fall of blood 

 pressure, a stoppage of secretions, and ultimately death by 

 cessation of respiratory activity. Normally animals are 

 protected from this poison by the lining membrane of 

 the alimentary canal, so that no proteose or peptone is 

 found in blood or lymph even during the most active 

 periods of digestion. The cells of this membrane possess 

 many remarkable properties, but one of the most impor- 

 tant is this power of regenerating albumin from peptone. 



Allied to the albumoses of ordinary gastric activity are 

 the similar products produced by bacteria. The way in 

 which bacteria produce disease has long been a matter of 

 dispute, but the problem appears to be approaching- solution. 

 Pathologists have at last turned their attention to the chemi- 



