Live Stock. 



134 



[August, 1911. 



The advantage of the method is evi- 

 dent ; it is, however, necessary that the 

 serum produced by hyperimmunization 

 with this fluid should be as potent as 

 possible in order to minimize the 

 amount of the dose necessary for pro- 

 tective purposes, especially as suscep- 

 tible animals such as hill, plateau, the 

 cross-bred European and Australian 

 stock require many times the protective 

 dose necessary for ordinary indigenous 

 plains cattle. 



The following observations were made 

 to test the power of serum produced 

 from the injection of peritoneal fluid 

 as compared with that produced from 

 the inoculation of virulent blood only. 



Plains animals are much less suscep- 

 tible than hill cattle and produce a 

 serum of less potency. The experiment 

 was therefore divided into two series, 

 viz.: (a) the comparison of plains serum 

 made from blood injections as against 

 that made from peritoneal fluid injec- 

 tions in these animals; (b) hill serum 

 made from blood inoculations as against 

 hill serum made from peritoneal fluid 

 injections. 



Charts 1 and 2 show the method em- 

 ployed in the serum preparation by 

 means of the inoculation of virulent 

 rinderpest blood into immunized plains 

 and hill cattle. 



Charts 3 and 4 show the method em 

 ployed for the preparation of the serum 

 by peritoneal fluid inoculations in plains 

 and hills. 



It has been found in this labor- 

 atory that the inoculation of doses 

 of peritoneal fluid cannot be increased 

 to the extent of blood doses. It has 

 apparently a much more toxic effect 

 and deaths have taken place as a result 

 of it within two to three days with all 

 the appearances of acute toxaemia. 

 (Plate I shows the post-mortem appear- 

 ance of the fourth stomach of a bull 

 which died on the third day after inocu- 

 lation.) Moreover, animals do not 

 absorb the material so well, and slough- 

 ing of the skin and abcesses are not in- 

 frequent from its use. It has been 

 noticed that an acute inflammation 

 sometimes follows, resulting in a dry 

 gangrenous condition of the skin which 

 eventually peels off as a hard scale, occa- 

 sionally necessitating the destruction of 

 the animal. 



These results are not apparent unless 

 very large doses, i.e., 3,000-5,000 c.c. are 

 given. With the same quantity of blood 

 no such result is seen. It is not caused 

 by the material being septic, as frequent 



examinations have shown that the fluid 

 is sterile, with the exception of rinder- 

 pest. Chart 5 shows the result of perito- 

 neal fluid injection, in which death took 

 place on the second day. There were 

 gangrenous areas at the seat of inocu- 

 lation, and the animal presented the 

 toxic post-mortem appearances described 

 above. Many similar results have been 

 obtained, and the post-mortem appear- 

 ances are always identical. 



It was therefore considered inadvis- 

 able to use more than the dose indi- 

 cated on the charts for the peritoneal 

 inoculations. Although these doses are 

 somewhat less than those of blood, they 

 are as much as can be given to ensure 

 absolute safety in their administration. 

 The post-mortem appearance in Plate 1, 

 showing the acute inflammatory condi- 

 tion, is very characteristic and always 

 seen. Chart 5 shows the course of 

 injection in an animal so inoculated. As 

 death took place on the second day with 

 the toxic post-mortem symptoms above 

 mentioned — rinderpest per se could not 

 have been the reason, and the conclusion 

 is that a toxaemia is the canse of death. 

 Plains animals are much more suscep- 

 tible to this toxic influence than hill 

 cattle. It is known that plains animals 

 are less susceptible to rinderpest than 

 the hill, and this may account for their 

 greater susceptibility to the toxin. The 

 results obtained in the Philippines with 

 peritoneal fluid are much better than 

 ours, and this may be accounted for by 

 the same reason, i.e., that all their 

 cattle are apparently as susceptible as 

 our hill animals. 



In both cases the rapid method of 

 making serum is adopted, i.e., plains 

 animals only one hyperimmunizingdose, 

 and for hills two hyperimmunizing 

 doses. Serums prepared by the above 

 methods were tested as follows : — 



The doses are arranged on a plains 

 animals basis, i.e., so many c.c, per 600 

 lb. of body weight. Lingard has shown 

 that hill animals require eighteen times 

 the dose necessary for plains animals,and 

 as these latter are invariably suscep- 

 tible, they were used for the test. 

 Doses of 2, 4, 6 and 8 c.c. per 600 lb. were 

 used to test the serum produced frpm 

 hill animals, and doses of 6, 8, 10, and 12 

 c.c. per 600 lb. for serum prepared from 

 plains animals. The doses were so 

 arranged because the serum of plains is 

 weaker than hills. In each case the 

 amount of the test dose is multiplied 

 eighteen times, because it is for hill 

 animals and doses given in exact propor- 

 tion as to weight in the ratio of 5 c.c. per 

 6001b. 



