498 INFECTION AND RESISTANCE 



tion has not been very extensive ; not all observers have been able to 

 obtain results as apparently reliable as those of Ascoli and his col- 

 laborators. It is not possible therefore to express a final opinion 

 regarding this method of investigation; it contains, however, an in- 

 teresting principle which with more exact methods of measurement 

 may well become very important in serum diagnosis. 



