Sources of Error 



85 



superadded in Nos. 3 to 5. Control tubes tested with anti-ox serum 

 showed general opacity in the last of the alkaline series and slight 

 clouds in the acid series. Similar experiments with 1 in 10 solutions 

 showed cloudings in the normal serum and first three specimens of the 

 alkaline series only. 



In the light of these observations it becomes necessary to test the 

 reaction to litmus of all solutions which are to be examined and, if 

 found decidedly acid or alkaline, to neutralize them. 



It must also be remembered that the addition of strong acid or 

 alkali to fluid or dried blood completely destroys it." 



The effects of the prolonged action of Acids and Alkalis on Fluid Sera. 



These experiments were continued by Graham-Smith (1903, p. 359) 

 as follows : 



" Ox, and sheep, sera with acids and alkalis added in the proportions 

 given below were kept under conditions similar to those just mentioned. 



