250 TYPHOID FEVER. MALTA FEVER 



Certainly, these instances show a good balance 

 of lives saved, not only under the adverse conditions 

 of the war, but also in Egypt, India, and the United 

 Kingdom. But the bacteriological work on typhoid 

 fever has been directed also to the working out of a 

 very different problem : and that is the method of 

 diagnosis which is called "Widal's reaction." The 

 practical uses of this reaction are of the utmost 

 importance. It is the outcome of work in different 

 parts of the world — by Wright and Semple and 

 Durham in England, Chantemesse and Widal in 

 France, Pfeiffer and Kolle and Grliber in Germany, 

 and many more. The first systematic study of it 

 was made by Durham and Pfeiffer ; and Widal's 

 name is especially associated with the application of 

 their work to the uses of practice. Admirable 

 accounts of the whole subject are given by Dr 

 Cabot in his book, The Serum- Diagnosis of Disease 

 (Longmans, 1899), and by Mr Foulerton in the 

 Middlesex Hospital Journal, October 1899 and 

 July 1901. 



Widal's reaction is surely one of the fairy-tales 

 of science. The bacteriologist works not with 

 anything so gross as a drop of blood, but with a 

 drop of blood fifty or more times diluted ; one drop 

 of this dilution is enough for his purpose. Take, 

 for instance, an obscure case suspected to be typhoid 

 fever : a drop of blood taken from the finger is 

 diluted fifty or more times, that the perfect delicacy 

 of the test may be ensured ; a drop of this dilution 

 is mixed with a drop of nutrient fluid containing 

 living typhoid bacilli, and a drop of this mixture 



