ANAEROBIC HABITATS 



31 



life while in the other (Atlantic Ocean) the oxygen de- 

 mands of planktonic organism.s are probably satisfied. 



3. THE INTESTINAL TRACT 



The intestinal tract of warm-blooded animals is an 

 important habitat for a great variety of parasites. The 

 contents of the intestine consist of more or less liquid 

 masses and of gases. Under ordinary conditions both are 

 quite poor in oxj^gen, as the analyses summarized in Ta^ 

 ble 3 and Table 4 show. 



TABLE 3 



Oxygen Context of Gas Mixtures Found in the Intestinal Tract of 



Warm-blooded Animals. 



Most figures represent mean values of several determinations. 



The source of the oxygen found in the liquid or gaseous 

 intestinal contents seems to be twofold. Some oxygen is 

 always introduced with the air that is swallowed together 

 with the food. Most of it seems, however, to disappear 

 rapidly already in the stomach, partly through absorp- 



