Scientific Proceedings. 



151 



of a very interesting experiment which bears out this theory. By 

 ligating all the muscles and blood vessels in the leg of a guinea 

 pig and then injecting the guinea pig with over a hundred fatal 

 doses of tetanus toxin below the ligatures, the pig did not develop 

 tetanus, but they were able to demonstrate a slight amount of 

 tetanus toxin in the sciatic nerve ; in other words, all flow of lymph 

 to the limb was prevented except that which entered through the 

 skin, and therefore there was only a slight flow of lymph up to the 

 nerve. 



The conclusion is then that tetanus toxin does not travel up 

 the nerve by reason of any specific attraction of the nervous tissues, 

 but because the lymphatic flow in the nerve is from the periphery 

 toward the center. 



104 (247) 



On the formation of a specific precipitin in rabbits after in- 

 oculation with colloidal platinum and colloidal silver. 



By CYRUS W. FIELD. 



[From the Research Laboratory of the Department of Health, of 



New York City.~] 



Some time ago in testing the precipitating effect of rabbit serum 

 on various positive and negative colloids I found that such serum 

 precipitated colloidal platinum and colloidal silver to a fair degree. 

 Serum from one rabbit precipitated colloidal platinum completely 

 at 1- 1 00, slightly at 1-200 and not at all at 1-500. This serum 

 precipitated colloidal silver completely at 1-10, partially at I-IOO 

 and not at all at 1-250. After receiving three injections of col- 

 loidal platinum in three weeks this rabbit's serum then precipitated 

 colloidal platinum completely at 1-1,000, slightly at 1-1,250 and 

 not at all at 1-1,500. Whereas it precipitated colloidal silver 

 completely at 1-100, slightly at 1-250 and not at all at 1-500. 



Serum from another rabbit originally precipitated colloidal 

 platinum completely at 1-50, partially at 1-100 and not at all at 

 1-250. The same figures held good for colloidal silver. After 

 three injections of colloidal silver during three weeks, this rabbit's 

 serum precipitated the colloidal silver completely at 1-500, par- 

 tially at 1-1,000 and not at all at 1-1,250, whereas colloidal 



