THE RELATION OF LIPOIDS TO IMMUNITY 563 



tion. Keidel and Kurwitz report positive reactions with luetic serums 

 in about 75 per cent of their cases. The reaction was found highly 

 specific in that syphilitic extracts gave negative reactions with serums 

 of non-syphilitic persons and patients suffering from malignant disease. 

 Extracts of normal fetal liver and beef heart gave negative reactions 

 with serums of syphilitic persons. 



Positive reactions have also been found in malignant disease, as with 

 the antigens of carcinoma and sarcoma. Keidel and Hurwitz obtained 

 16 positive reactions in a series of 24 serums of persons suffering with 

 definite or suspected malignant disease. Burmeister did not find the 

 reaction of value in cancer. 



The epiphanin reaction has also been used in the diagnosis of preg- 

 nancy, but sufficient work has not been done to render an expression as 

 to its merits of value at this time. 



THE MIOSTAGMIN REACTION 



Among the very large number of immunity reactions employed in 

 attempts to secure a diagnostic test for cancer, the "miostagmin reac- 

 tion" of Ascoli and Izar 1 is the only one thus far devised that claims 

 the serious attention of the clinician. 



Principles. This reaction is founded on the fact, noted by Ascoli, 

 that by the mixing of an antigen and its corresponding antibody there 

 results a reduction of the surface tension of the liquid containing these, 

 which may be demonstrated by counting the number of drops of the 

 fluid in a given volume (usually 1 c.c.), under constant conditions. 

 Normal serum diluted with salt solution is first tested, and the number of 

 drops found in a cubic centimeter determined with a specially devised 

 instrument known as Traube's stalagmometer. The antigen is so diluted 

 that when mixed with this normal serum it does not increase the number 

 of drops more than one in a cubic centimeter. When properly diluted 

 patient's serum and antigen are mixed, it may be found that the number 

 of drops is increased from 2 to 8 in a cubic centimeter. This constitutes a 

 positive reaction. The reaction is apparently due to the lowering of sur- 

 face tension, so that more and smaller drops are found; hence the term 

 "miostagmin" has been applied to the test, the word being devised from 

 the Greek, meaning "small drop." 



The reaction is said to be sharply specific and very delicate, so that 

 antigens diluted up to 1 : 100,000,000 or higher may be detected. The 

 technic requires considerable practice and experience or erroneous 

 results are quite likely to occur. 



1 Miinch. med. Wochenschr., 1910, 57, 62, 182, and 403. 



