122 



The Nature of Precipitm Reactions 



kept for some time and consequently show the combined results of age 

 and putrefaction. 



Normal 

 Anti-ox rabbit 



Anti-human 



The above table shows that in some cases advanced natural 

 putrefaction seems to exert little influence, for although the precipitum 

 is decreased considerably in Nos. 4, 5, and 6, yet this is not the case in 

 Nos. 3 and 8. All the specimens had been putrefying for the time 

 given in each case. Though time may have influenced Nos. 4, 5, and 6, 

 it is more probable that organisms whose growth deleteriously affected 

 the serum were present. 



Finally, from the few experiments we have done we are of the 

 opinion that putrefaction to almost any extent does not affect the 

 specific precipitum-forming body. 



Since blood dried in small quantities does not undergo putrefaction 

 to any appreciable extent this factor may be neglected in ordinary 

 medico-legal work. 



Experiments quoted on p. 124 with contaminated anti-human and 

 anti- fowl's albumin sera likewise demonstrated that putrefaction in 

 sealed tubes does not affect the antibody in them, as has also been 

 found by Nuttall. 



An experiment conducted on the same blood dilution with a normal 

 and a contaminated sample of the same antiserum gave as a mean of 

 four estimations in each case '0433 c.c. and '0436 c.c. of precipitum 

 respectively. 



Moreover putrid (filtered) sera when injected produce, as several of 

 us have found, powerful and specific antisera, and Strangeways has 

 shown that the power of antisera made with similar doses of fresh and 

 putrid filtered sera is nearly identical." 



