104 



Scientific Proceedings (29). 



From these investigations the conclusion can be drawn that 

 the experimentally produced deciduomata differ in the rabbit and 

 in the guinea-pig in the same way as the natural placentas do. 

 Whether the dissimilar reactions of homologous tissues to similar 

 stimuli in the rabbit and in the guinea-pig depend upon a difference 

 in the structure of the protoplasm, or upon a quantitative or quali- 

 tative difference of the internal secretion of the ovaries, or upon a 

 combination of these two factors, are questions which cannot be 

 answered at present. 



61 (317) 



Hemolytic action of the venom of Heloderma suspectum. 

 By Elizabeth Cooke and Leo loeb. 



[From the Laboratory of Experimental Pathology, University 

 of Pennsylvania.] 1 



1. The venom of Heloderma suspectum alone does not cause 

 hemolysis of blood corpuscles (ox, sheep, dog, guinea-pig, rabbit, 

 Heloderma, frog). Fresh and dried venom behave alike in this and 

 other respects. It must be mentioned that on a few occasions 

 guinea-pig corpuscles showed a trace of hemolysis with venom 

 alone, but as this usually did not occur, it is likely that the corpus- 

 cles which behaved as exceptions, had, in some way, lost part of 

 their natural resistance. 



2. In combination with lecithin the venom causes hemolysis. 

 The amount of lecithin necessary varies for corpuscles of different 

 species. 



3. Certain blood sera, heated or unheated, act like lecithin 

 (dog, horse, turtle), others do not (guinea-pig, rabbit, ox, sheep, 

 Heloderma). Only those activate which are supposed to act 

 through lecithin, not those which act through complement. 



4. A number of non-activating sera, heated or unheated, inhibit 

 the venom-lecithin hemolysis. Different sera possess different in- 

 hibiting values, the greatest observed inhibition being due to Helo- 

 derma serum and the next greatest to guinea-pig serum. But the 



1 These experiments represent part of an investigation upon the toxic action of 

 venom of Heloderma carried out in this laboratory under a grant from the Carnegie 

 Institution. 



