6o 



Scientific Proceedings (79). 



constant occurrence of lichenase in the digestive tract of the in- 

 vertebrates studied, suggests that the ability to hydrolyze lichenin 

 may be a characteristic of invertebrates as contrasted with verte- 

 brates. The presence of an inulase or raffinase in the species 

 studied was not constant. Lichenase to judge from the present 

 series of experiments is not invariably associated with inulase as 

 has been suggested (existence of an inulo-lichenase). The follow- 

 ing species were studied; sponge, earthworm, leech, starfish (2 

 species), sea urchin, chiton (2), mussel (3), snail (2), crab (2), 

 shrimp, grasshopper, tunicate, gold fish, frog (adult and tadpole 

 stages), horned toad, garter snake, terrapin (2), domestic fowl, 

 wild rabbit, pig, sheep, dog, and man (saliva). The strongest 

 reactions were obtained with the star fish (Asterias ochracea), 

 snail (Planorbis trivolvum) , and grasshopper (Melanoplus differ- 

 entialis) . 



38 (1216) 



Further studies in serum sickness. 



By Richard Weil, M.D. 



[From the Department of Experimental Therapeutics, Cornell Uni- 

 versity Medical School.] 



In a previous paper, 1 I showed by anaphylactic methods that 

 the blood of human beings who had received large injections of 

 therapeutic horse serum contained not only horse serum, but anti- 

 bodies thereto, at some stage of the serum sickness. Since that 

 time I have approached the same problem by means of the pre- 

 cipitation method, which is very much the more delicate method 

 for the purpose. Remnants of horse serum in the blood are dem- 

 onstrated by precipitation with the serum of a rabbit immunized 

 to horse serum. Antibodies to horse serum are demonstrated by 

 precipitation of horse serum by the human serum. By this method 

 it has been possible to demonstrate the presence of horse serum 

 in the blood from the time of injection up to more than twenty-one 

 days thereafter, in constantly diminishing amount. Antibody is, 

 as a rule, demonstrable within seven to ten days after the thera- 



1 Weil, R., Proc. Soc. for Exp. Biol, and Med., 1914, xii, 37. 



