538 INFECTION AND RESISTANCE 



methylene blue could be observed to diffuse across in the tube in 

 which antigen and antibody had been present and not in the con- 

 trols. Many modifications of technique to demonstrate this principle 

 have been made by Weichhardt himself, and since the reaction is not 

 likely to find much immediate diagnostic application because of its 

 great delicacy, we need not describe them at length but refer the 

 reader to Friedemann's excellent description in the Kolle and Wasser- 

 mann, second edition, Vol. III. 



Similar in principle but by no means identical is the so-called 

 Meiostagmin reaction, chiefly developed by Ascoli. 



THE MEIOSTAGMIN REACTION 



Ascoli and Izar 31 have attempted to work out a diagnostic reac- 

 tion which depends upon an alteration of surface tension of a fluid 

 when an antigen unites with its specific antibody. Ascoli in his first 

 experiments worked with typhoid bacillus extracts and the sera of 

 typhoid patients, and found that when the two suspensions were 

 mixed a reduction of surface tension resulted after time for union 

 between the two had been allowed. 



They determined the reduction of surface tension by Traube's 32 

 method by the use of apparatus spoken of as the "stalagmometer." 

 The principle of this method depends upon the fact that as surface 

 tension is reduced the number of drops to a given quantity of fluid 

 is increased. 



Diluted serum of patients was mixed with diluted antigen, and 

 the number of drops contained in one cubic centimeter of the mix- 

 ture was immediately determined and again measured after the mix- 

 ture had remained for two hours in the incubator at 37 C. An 

 example of one of Ascoli' s early measurements is given in the protocol 

 cited below. 



Of course a certain amount of reduction of surface tension results 

 when various antigens are brought together with normal sera, but 

 this can be easily controlled by suitable dilution, and must be care- 

 fully taken into consideration in each individual case. Ascoli and 

 Izar have applied this method to the diagnosis of tuberculosis, ty- 

 phoid, and various other diseases, and have reported what seemed to 

 them reliable results. So far experience with the meiostagmin reac- 

 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. 



31 Aseoli and Izar. Munch, med. Woch., Nos. 2, 7, 18, 22, 41, 1910. 



32 Traube. Pfliigcr's Archiv, Vol. 123, 419. 



