PRINCIPLES OF VETERINARY SURGERY 171 



tors, they are shed into the plasma, where they unite with 

 the cholera bacilli for which they are specific, and so affect 

 them that the bacteria become non-motile, and stick to- 

 g-ether, forming clumps, i. e., they are agglutinated. The 

 receptors thus have two characteristic groups; out, a hap- 

 tophore which combines with the bacterial cell, and another 

 the zymophore, or agglutinating property, which agglutin- 

 ates the cells. 



Similar to the action of the agglutinins is that of the 

 precipitins. If a rabbit is repeatedly injected with ox-blood, 

 his tissue-cells' are stimulated to form receptors which fit 

 ox-blood only. After a few days, the cells shed receptors 

 into the serum. Now, when this rabbit's serum is mixed 

 with ox-blood, the receptors, through their haptophores. 

 unite with certain chemical substances in the ox-blood, 

 which they precipitate by means of their zymophores. This 

 zymophore portion of the receptor corresponds to the toxo- 

 phore portion of the toxin molecule, and the complemento- 

 phile portion of the complement. The zymophore group 

 consists of a ferment which has the peculiar property of 

 causing certain cells to agglutinate, or to form precipitate 

 in other cases. 



AGGLUTININS: — These have a large practical value 

 in veterinary science, in that they are of valuable aid in 

 diagnosis. The agglutination test has taken its place 

 among the routine methods of diagnosis, and has the ad- 

 vantage of being pathognomonic, in that it will diagnose 

 certain bacteria, — the glanders bacillus, hog cholera, tuber- 

 cle bacillus, bacillus dysenterise, streptococcus and many 

 others. The test is as follows : 



Cover-Glass Method: — Let us take, for example, the 

 hog cholera bacillus. Obtain a drop of blood from the sus- 

 pected animal, and let it dry on a slide or piece of paper. 

 Then get a culture of known hog cholera bacilli, preferably, 



