596 CLINICAL VETERINARY MEDICINE AND SURGERY. 



As early as 1881 M. Bouchard had succeeded in increasing the re- 

 sistance to the pyocyanic bacillus by injecting into the rabbit's veins 

 blood or serum obtained from the dog. Shortly afterwards he found 

 that the serum possessed similar immunising powers and produced the 

 same therapeutic effects as blood itself. 



Starting with these facts and the then very general belief that 

 goats were refractory to tuberculosis MM. Bertin and Picq subjected 

 rabbits inoculated with tuberculosis to injections of goats' blood. 

 According to their observations this fluid in doses of 2*50 grammes 

 per kilo of body-weight checked the development of the disease, and 

 even cured animals when treatment was commenced shortly after 

 inoculation. These authors and M. Bernheim applied this method of 

 treatment to man; M. Lepine also tested in man the effects of injecting 

 goat's serum. 



The experiments undertaken by M.Bouchard in i8gi, and published 

 in January, 1892, show that the blood and serum of animals which are 

 refractory (or were so considered), and of the goat in particular, far 

 from having a favourable influence when injected into tuberculous 

 animals often appeared to exercise an absolutely injurious effect. He 

 says : — " As a whole the cases inoculated have been graver and more 

 rapidly fatal in the guinea-pigs treated than in the control animals." 



The end of the year 1890 had been marked by an important dis- 

 covery which inaugurated the era of sero-therapy. Behring and 

 Kitasato had discovered the existence of anti-toxic substances in the 

 fluids of animals vaccinated against tetanus and diphtheria. They 

 had found that the blood of animals rendered refractory, either by 

 Nicolaier's or Loffler's bacillus, had the power of neutralizing or 

 rendering harmless the toxins of these bacilli ; that this property ex- 

 tended to the serum as well as to the unaltered blood ; and that it 

 permitted of definite treatment. Everyone knows the results of sero- 

 therapy in diphtheria and tetanus. 



Attempts were, therefore, made to effect for tuberculosis what had 

 been done for tetanus and diphtheria ; efforts were made to immunise 

 animals (goat, sheep, dog, horse), to bring about by various methods 

 the production of tuberculous antitoxins in the bodily fluids of these 

 animals. Numerous experiments were undertaken with this object. 

 We should specially mention those of MM. Hericourt and Richet, 

 who prepared serum-yielding animals by injecting them with virulent 

 tuberculous cultures, both human and avian ; those of Behring, who 

 produced an antitoxic serum by injecting different animals with tuber- 

 culin ; of Nieman, who prepared dogs and goats by injections with an 

 alcoholic extract of tuberculin ; of Maragliano, who first injected all 



