Sources of Error 



77 



"As an example of the important volatile antiseptics chloroform may 

 be taken. In solutions containing much of this reagent on the 

 addition of serum a white cloud, and later a deposit, occur. More 

 dilute solutions give rise to slight cloudings. The results of experiments 

 with a series of such volatile antiseptics are given below. When only 

 present in small quantities in preserved sera the possible error due to 

 their presence can be eliminated by placing them in the incubator for 

 half-an-hour to evaporate off the reagent. When present to a greater 

 extent it was found that the supernatant serum above the deposit 

 caused by them still retained its specific properties. This is in accord 

 with what Nuttall has found. 



110 

 1100 



11000 



1_10,000 



1100,000 



(30 mins. 

 124hrs. 



See Footnote. 



Corrosive sublimate and ferrous and copper sulphates were found 

 to produce very marked effects. They apparently destroy the serum 

 in contact with them and except when present in very small quantities 

 it was found impossible to carry out the test. The effects of dilutions 

 of corrosive sublimate and copper sulphate are given below. 



In this and other tables by these authors the following symbols have been used : 



C = coagulation. 

 + = marked cloud full reaction. 

 + = less marked cloud, 

 x = medium cloud. 

 # = slight cloud. 

 #? = very slight cloud. 



D = large deposit after 24 hours. 

 D = smaller ,, ., 

 d = smaller ,, ,, ,, 

 tr = trace of deposit. 

 . = no result. 

 = no reaction. 



