464 HORSE, SWINE AND POULTRY DISEASES 



ant holds the hog firmly by the tail. A hogholder or rope with slip- 

 noose may be placed over the hog's upper jaw, the rope being then 

 snubbed to a fence post. The treatment is not painful to the pigs 

 which usually cease resistance while the injection is taking place. 

 (Mich. Cir. 6.) 



Doses of Serum. The amount of tested serum to use per ani- 

 mal is approximately as follows : 



Under 25 Ibs. weight 15 cubic centimeters 



For 100 " " 25 cubic centimeters 



200 " " 40 cubic centimeters 



" 300 " " 50 cubic centimeters 



400 " " 60 cubic centimeters 



500 " " 70 cubic centimeters 



(N. J. L. S. C. Cir. 1.) 



Which Method to Use. Properly prepared serum when used 

 alone, without the employment of blood from a sick hog, is entirely 

 harmless and incapable of giving rise to an attack of hog cholera. 

 Nor does this injection interfere in any way with the growth of the 

 treated hogs. The simultaneous inoculation, involving as it does the 

 use of a disease-producing virus, requires much more care when em- 

 ployed than does the serum-alone inoculation, for, if through careless 

 preparation or from any other cause the serum should be weaker 

 than is required, injury to the vaccinated hog might result. This 

 danger, which is extremely slight when carefully tested serum is 

 used, is met with in practically all processes which are now employed 

 for producing a permanent and lasting protection against infectious 

 diseases, and although it would be very desirable to eliminate even 

 this slight element of danger, we can hardly expect to do this without 

 at the same time sacrificing to some extent the high degree of immu- 

 nity and the prolonged protection which follows the simultaneous 

 method in its present form. 



Practically, in deciding which method to use one must be gov- 

 erned largely by the length of immunity which is required. If this 

 is needed for only a few weeks, or if the treatment can be repeated at 

 short intervals, as in the case of exceptionally valuable pure-bred 

 hogs, where the increased cost would not be objected to, the serum 

 alone may be used. In other cases the simultaneous method is rec- 

 ommended. In either process of vaccination it is considered highly 

 desirable for the treatment to be applied by competent veterinarians 

 who have had special training in this class of work, and only such 

 skilled men should employ the simultaneous process. After treat- 

 ment by the simultaneous method the herd should be kept under ob- 

 servation for ten days or two weeks, and if any of the inoculated hogs 

 show serious symptoms of disease the herd should be immediately re- 

 treated with the serum alone. When properly performed, the simul- 

 taneous inoculation does not seem to injure the hog or to interfere 

 with its growth in any way, and if the precautions indicated above 

 are taken it is regarded as safe enough for practical use. (F. B. 379.) 



Results of the Serum. When the serum is potent and the work 

 properly done, the hog seldom loses a feed. The serum, however, 



