Effects of Filtration, Putrefaction, etc. 119 



but returned to the normal after 110 c.c. had been filtered. No change 

 was noticed during the passage of a further 300 c.c. through the filter. 



In the latter case the precipitum-tbrming property diminished 

 rapidly and fairly uniformly as the filter became choked." (Graham- 

 Smith, 1903, p. 357.) 



Ox serum. 



Quantity altered 



New Berkefeld filter 



New clean Chamberland filter 



.. 

 Percentage 



100 



97 

 97 



87 



56 



56 

 40 

 40 



The Precipitint and Precipitable Substances resist 

 Putrefaction and Desiccation. 



I have already noted elsewhere that putrid antisera might 

 retain unimpaired precipitating power for their homologous bloods. 

 I have found this to be the case repeatedly, having found a variety 

 of microorganisms, moulds 1 , Bacilli and Cocci, present in such sera, 

 the latter at times emit ting a very putrid odour. Similarly, putrid 

 bloods have been found to react to their homologous antisera both 

 by Uhlenhuth, Nuttall (1901), and Biondi (1902), the latter incidentally 

 mentioning that he obtained positive reactions with human blood 

 ingested by tleas. bugs, ami mostmitos. In my paper of 1, vn. 1901, 

 I stated that human blood which had undergone putrefaction for two 



1 Confirmed by Bioudi (1902, p. 17). 



