CLINICAL EVIDENCE OF VALUE OF SERUM 491 



probable that a second injection with serum might have saved this 

 animal. Several of the treated boars showed slight symptoms of 

 the disease even after treatment, but they finally mastered the 

 disease and recovered. 



Of the 38 treated shoats, only 3 died. It will be recalled that 

 2 of these showed signs of probable infection at the time of treat- 

 ment. The old sow which served as a check became sick and died. 

 The other old sows which were treated remained well. All of the 

 treated sucking pigs in both htters remained well, while all of the 

 checks in both litters died. This was, indeed, a remarkable 

 showing, and one which in itself should convince even the most 

 doubtful that there is, indeed, something in the serum treatment. 



Of the 27 untreated shoats left as checks, all died but 5. Here, 

 again, we have a most striking example of what will happen even 

 in a well-cared-for herd without the use of the serum treatment. 



It will be noted in this herd that the results accomplished were 

 quite a bit better than in some of the other herds treated under 

 somewhat similar conditions. The explanation of this is in part 

 to be found, I think, in the fact that larger doses of serum were used 

 in this herd than have been reported in the preceding herds. 

 Serum, while a great agent, must be given in large enough dosage 

 to combat the infection present. This is especially the case where 

 a herd is being treated that is already infected. 



It will be noted in this last herd that the dose of serum used 

 in the sucking pigs was 20 c.c. instead of the dose of 10 c.c. which 

 had been used in a number of the other sucking pigs treated. The 

 brilliancy of the results in this last herd speaks most eloquently 

 for the use of the larger dose of serum. 



It must be remembered that in these young pigs a compara- 

 tively larger dose of serum is required than in the larger animals. 

 It is a question in my mind whether a dose of less than 15 c.c. of 

 serum should ever be given. Especially I do not beheve that less 

 that 15 c.c. of serum should be administered if -there is presence of 

 infection in the herd. The resisting power of the body of these 

 little fellows is very weak, and what protection they get is re- 

 ceived almost entirely from the serum injected. In the older ani- 

 mals there is a considerable amount of natural resistance on the 

 part of the tissues of the body, and this allows us to use a somewhat 



