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VERA DANCHAKOFF AND S. M. SEIDLIN. 



have occasionally been observed in the adult to succeed in com- 

 pletely digesting heterogenous proteins, as for example, catgut 

 of mammalian origin which is digested by the stroma cells of 

 different animals. Though suggestive of a widespread digestive 

 power of the mesenchyme, these observations do not allow any 

 definite conclusions regarding its extent and its various aspects. 

 Finally, the question has hardly been raised, as to whether a 

 digestive activity temporarily developed by the mesenchyme or 

 by its derivatives in a definite region, might not have a general 

 effect upon the whole organism of the animal under experiment. 

 In this connection, the production of induced immunity against 

 tumors by introduction into the organism of particles of tissue 

 of the same species as that bearing the tumor and the immunization 

 against pathogenic bacteria by introducing the same organisms in 

 a weakened state, is of interest. As to how a local process dis- 

 played in a well-defined region of the organism can influence 

 its general properties and through what mechanism this can be 

 effected, only few hypotheses and even less data can be found. 



In order to approach the problems stated above, different 

 heterogenous, non-injurious proteins should be introduced among 

 stroma cells other than those of the spleen. The study of their 

 digestion, especially when excessive amounts are introduced, 

 would throw light upon the question as to whether easily mobiliz- 

 able cells from remote parts of the organism will participate in 

 this process along with the cells found in close proximity to the 

 injected masses. The study of the digestion of the substances 

 introduced should be pursued not only until its completion, but 

 special care should be given to the fate of the phagocytes, and a 

 method should be devised for identifying them in any part of 

 the organism which they might enter, either in a passive way or 

 by their own active movements. Rather small animals only can 

 be used, the size of which would not offer insurmountable dif- 

 ficulties for the study of the final distribution of these phagocytes. 

 A favorable object for such studies has been found in the 

 tadpole. Various amounts of different heterogenous proteins, in- 

 soluble in saline, such as edestin, fibrin, coagulated egg albumin, 

 were introduced into the transparent tail. When it was found that 



