BIMUNITY 75 



The antibodies concerned in this reaction are called 

 precipitins. The precipitin test is now made use of in 

 criminal cases where it is necessary to determine 

 whether certain blood-stains are from human blood or 

 otherwise. This reaction may also be used to determine 

 whether sausage contains any horse meat. In addition 

 to the foregoing, still other antibodies are known. 

 When ferments are injected into an animal, the latter 

 responds by producing antiferments. ^^'hen certain 

 antibodies are injected, anti-antibodies are produced. 

 The entire subject is extremely complex, and further 

 discussion in such a work as this is out of place. 



Anaphylaxis. — ^When albuminous substances are taken 

 into the body through the mouth, that is, into the stom- 

 ach and intestines, they are acted on by certain ferments, 

 digested, and serve as body nourishment. When, how- 

 ever, they are introduced through other channels — e. g., 

 by means of hypodermic, intramuscular, or intra- 

 venous injection — they cause the production of anti- 

 bodies as was described above. Some of these antibodies 

 appear to have digesting properties; at least they split 

 up the injected material, evidently so that the body 

 may get rid of it. Recent studies have shown that this 

 non-intestinal splitting up of albuminous substances 

 may give rise to serious symptoms, and that the rashes 

 sometimes following the injection of diphtheria anti- 

 toxin are due to this cause. It has been found that such 

 rashes are more likely to follow second injections. In 

 experimenting with guinea-pigs it is possible to so 

 arrange matters that the second injection will prove 

 fatal. This phenomenon is spoken of as anai)hylaxis. 



