Sources of Error 



79 



in salt solution were made, and all were allowed to stand in open 

 dishes for 2 hours in order that the volatile antiseptics should evaporate 

 off The results were compared with serum kept under the same 

 conditions but without the addition of any antiseptic. The following 

 table shows that in nearly all cases the precipitum-forming power was 

 slightly reduced, but in a few completely destroyed. 



The effects of the presence of these substances in fluids to be tested 

 have been given above. 



Ox serum 

 Precipitum Percentage 



0356 

 0338 

 0328 

 0187 

 0300 

 0300 

 0281 

 0281 

 0187 

 0225 



0347 

 0244 

 0262 



0187 

 0169 



0262 

 0262 



100 

 95 

 89 

 55 

 84 

 84 

 79 

 79 

 55 

 63 



97 



68 



73 











55 



47 















73 



73 



Sheep serum 

 Precipitum Percentage 



0140 100 



0103 73 



0093 

 0140 



0112 

 0140 



0084 



0075 

 0103 



0112 



65 



100 



80 

 100 



60 



53 

 73 



80" 



The results obtained by Graham-Smith and Sanger with carbolic 

 acid and chinosol are considered on page 82, those obtained with lime 

 in Section IX. 



5. The acid or alkaline reaction of the medium. 



Normal blood dilutions possess an alkaline reaction. Tchistovitch 

 (v. 1899) found that precipitation only took place when the reaction 

 was alkaline ; when it was neutral, a slight opalescence was observable ; 

 no reaction took place when the reaction was acid. Linossier and 

 Lemoine (21, III. '02) found that sulphuric acid in the proportion of 

 49 : 1000 lessened reaction, that it was reduced to a minimum when 



