METHODS OF SERO-DIAGNOSIS. 2L1 



sometimes used in addition to these other two. In some places 

 the methods of complement fixation and agglutination have re- 

 placed the use of mallein, but it must be remembered that they 

 are purely methods which can only be carried out by workers in 

 laboratories. 



The practical use of these methods has also been indicated 

 in the case of contagious abortion in cattle. The agglutination 

 test is of service also in the diagnosis of infection of the domestic 

 animals, and more especially the goat, with the micrococcus 

 melitensis, the causal agent of Malta or Mediterranean fever of 

 man. Here it may be remarked that Bruce has shown that the 

 disease known amongst the natives of Uganda as " Muhinyo " is 

 the same as Malta fever. It must be pointed out here that by 

 these methods not alone can we demonstrate the presence of 

 specific antibodies when we are in possession of their respective 

 antigens, but that also we can reverse the process when we possess 

 a serum containing specific antibodies, in utilizing it to demon- 

 strate the presence or otherwise of their antigens ; and this method 

 is made much use of in the laboratory in determining the rela- 

 tionships of bacteria derived from different sources, or of bac- 

 teria which are morphologically very similar and whose species 

 are not easily distinguished by cultural methods, such as those 

 of the typhoid, para-typhoid, colon groups and others. 



It is of interest here to note that Ascoli and Valenti have 

 comparatively recently applied to the diagnosis of anthrax a 

 form of the precipitin formation test which is said to be of great 

 value in diagnosing this disease, being, for all practical purposes, 

 of a specific nature ; and, further, advanced decomposition or 

 marked putrefaction of the carcase from which the material to 

 be examined is obtained seems to make no difference as far as 

 the value of the test is concerned. 



The above-mentioned methods are those which have, up to 

 the present time, been extensively used in pathological diagnosis ; 

 but it is hardly justifiable to conclude this paper without reference 

 to some other methods whose value we can not yet properly 

 estimate, since much more experimental work must be done before 

 their every-day use can be justified. One of these methods is 

 that of diagnosis by means of utilization of the phenomenon of 

 Anaphylaxis. This term is one created by Richet in 1902, and 

 indicates a condition the opposite of that of protection, and, in 

 which the organism manifests a state of increased sensibility to 

 a second introduction under certain conditions, of materials which 

 exerted no, or only very slightly, harmful effects at the time of 

 the first inoculation. 



Richet was working at the time chiefly with a toxin (actino- 

 congestin) obtained from the tentacles of the marine animal 

 Actinia, and found that when he injected into dogs doses of this 

 toxin from which they recovered, that a second injection of the 

 same material, used after a certain time and in a much smaller 

 dose than that used on the first occasion, could cause their death, 

 and in most cases their death occurred almost immediately after 

 this second injection. 



