ADDENDA, 



THE CHEMISTRY OF ANIMAL PARASITES. 



Some parasites cause harm mechanically and pre- 

 sumably in no other way. In most of them there is 

 more or less evidence of the formation of a poison- 

 ous substance. Little, is as yet, known of the chem- 

 istry of avnimal parasites or their excretions. It is 

 known that the cells, at least in part, differ in 

 chemical composition from the cells of the higher 

 animal organisms. Chitin is one substance that con- 

 stitutes a large part of the outer coverings of en- 

 cysted parasites as well as the outer portion of many 

 of the worms. 



A chemical study of the bodies of the strongiles 

 show their bodies to yield fats, fatty acids consisting 

 principally of butyric acid, soaps, mucin, albumoses, 

 purin bases and creatin. A ptomain, a crystalizable 

 alkaloid, an amino acid and an amorphus substance 

 containing non-protein nitrogen and phosphorus which 

 gives precipitating reactions for an alkaloid. The cuti- 

 cle contains a protein like substance which has no rela- 

 tion to chitin. An alcoholic extract of these parasites 

 possesses strong hemolytic properties. The soaps, 

 fatty acids, crystalizable alkaloids and ptomains are 

 active in this hemolytic process. The parasites secrete 



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