1896.] rapidly producing Diphtheria Aniitoxines. 295 



-unsettled the question as to how far the acquired immunity produced 

 by the serum toxine is due to increased tissue resistance, or to the 

 presence of the antitoxine in the fluids of the body.] These results 

 are shown in the appended table (Table III). 



Table III.— Horse No. 3. 





Antitoxic yalue 

 of serum. 



Amount of toxines injected. 



21st day 



TbJ5 c.c. 

 ICo C.C. 

 STo CC. 



TaVo C *C. 



1200 c.c. serum toxine. 

 980 c.c. serum toxine. 



650 c.c. serum toxine and 1050 c.c. weak 



broth toxine. 

 1100 c.c. serum toxine and 1200 c.c. stronger 



broth toxine. 



Although the serum toxine had been used primarily in the expecta- 

 tion of rapidly immunising the animal, and thus shortening the 

 necessary period of treatment, the very high antitoxic value of the 

 serum obtained from horses Nos. 2 and 3 suggested that the method 

 might be applied effectively at a later stage. For the purpose of 

 testing this a number of horses which had been under the ordinary 

 treatment for from six to nine months were very kindly placed at my 

 disposal by Dr. Woodhead. In the first experiments 200 or 300 c.c. 

 of the serum toxine was mixed with the ordinary broth toxine, and 

 injected as usual. The results obtained, although slightly better, 

 were not at all so marked as one might have expected. On examining 

 more in detail the horses in which the best results had been obtained, 

 it was found that these had been under more or less continuous 

 treatment with the serum toxine, both toxines being injected as fre- 

 quently and in as large amounts as possible. Guided by these facts 

 four of the horses (Nos. 4, 5, 6, 7) received one evening each 300 c.c. 

 of serum toxine, and on the following morning an injection of weak 

 broth toxine. Although the quantity of weak broth toxine would, 

 under normal conditions, have produced hardly any effect, it produced 

 on this occasion most marked local and constitutional reactions. 

 During the remainder of the week these horses received injections of 

 weak broth toxine each day, or on alternate days according to their 

 condition, and on each occasion these gave rise to quite definite con- 

 stitutional and local reactions. During the following week an injection 

 of 300 c.c. of serum toxine was introduced, succeeded by similar 

 quantities of weak broth toxines, as in the previous week. [It will 

 be observed that all these horses received practically the same quan- 

 tities of toxine, with the exception of horse No. 5, in which the 



