296 ARCH E. COLE 



The organisms which Pasteur discovered were able to Uve 

 in the absence of oxygen (in a medium where reduced methylene 

 blue showed no signs of reoxidation) are now well known, and 

 their relationship to oxygen is generally admitted. Since that 

 time much work has been done to determine the resistance of 

 various animals to the lack of oxygen, and the metabolic mechan- 

 ism which enables certain of them to live for varying periods in 

 its absence. 



Thus Pflliger (75) found that frogs were able to live for a 

 period of twenty-four hours in an atmosphere of pure nitrogen. 

 He determined that their carbon-dioxide output varied very 

 slightly from that during a similar period in air. 



Bunge ('83, '90) pointed out that an intestinal parasite of the 

 cat, Ascaris mystax, can live for days in an oxygen-free saline 

 solution and continue to produce carbon dioxide. He affirms 

 that even when oxygen was available, the worm was unable to 

 utilize it. 



Putter ('06, '08), working with leeches. Lesser ('10), with 

 earthworms, and Weinland ('06), with pupae of flies, each pointed 

 out that the metabolic processes could go on for varying periods 

 of time in the absence of oxygen. 



Krogh ('16), in summing up the work relating to metabolism 

 of animals in an anaerobic environment, appears to believe with 

 other workers in the field that in an absence of oxygen an incom- 

 plete breakdown, anoxybiosis, of food-stuffs takes place, resulting 

 in the production of toxic products. Some animals are able to 

 excrete these toxic substances more readily than others. An 

 accumulation of the products of anoxybiosis probably inhibits 

 the catabolic reactions which causes eventual death. 



Weinland ('01) concluded from experiments on Ascaris living 

 in an oxygen-free environment that the carbohydrates were 

 chiefly catabolized, being broken down into carbon dioxide and 

 fatty acids. 



Packard ('07) found that fish lived longer in water free from 

 oxygen if they were previously injected with carbohydrates, 

 such as mannose or glucose. He assumed that the simple sugars 

 act as depolarizers in the process of protoplasmic respiration. 



