PRECIPITINS. 121 



cies of monkeys gave a slight but distinct reaction and a very faint 

 clouding appeared in the solutions of the bloods of the horse, ox and 

 sheep, all other bloods remaining perfectly clear. " The test gave 

 positive results when made with diluted human serum, pleuritic ex- 

 udation, both fresh and purulent, blood and serum which had been 

 dried on filter paper and on glass plates, with blood which had 

 undergone putrefaction for two months, with the blood of several 

 persons who had cut themselves (blood collected on filter paper), with 

 the serum from a blister on the foot following upon a long walk, and 

 with the serum from a blister following a burn on the hand. Both 

 nasal and lachrymal secretion gave a slight but decided reaction. A 

 faint clouding was produced in normal urine. That the precipitum 

 formed in putrid blood dilution was specific was proved by adding 

 the anti-sera of rabbits treated with ox, sheep and dog serimi to the 

 blood dilution, no reaction resulting." 



Nuttall concludes his investigations as follows : " (1) The investi- 

 gations we have made confirm and extend the observations of others 

 with regard to the formation of specific precipitins in the blood serum 

 of animals treated with various sera. (2) These precipitins are 

 specific, although they may produce a slight reaction with the sera 

 of allied animals. (3) The substance in serum which brings about 

 the formation of a precipitin, as also the precipitin itself, are re- 

 markably stable bodies. (4) The new test can be successfully 

 applied to a blood which has been mixed with those of several other 

 animals. (5) We have in this test the most delicate means hitherto 

 discovered of detecting and testing bloods, and consequently we 

 may hope that it will be put to forensic use." 



