250 GENERAL THERAPEUTICS FOR VETERINARIANS 



grams of blood-serum must be injected and it must be obtained from horses 

 in the same stable which had recovered from the disease and which had been 

 free from fever for at least 3 to 6 weeks. As Topper did not make his vacci- 

 nations until 4 to 6 weeks after the appearance of the disease, Schwarznecker 

 pointed out that it was very questionable whether the cessation of the out- 

 break was due to the vaccinations or to the natural course of the epizootic. 

 The Prussian military report for 1898 shows that the protective vaccination 

 with blood-serum is of no practical value. Contagious pneumonia did not 

 prevail as long in those divisions of the army in which no vaccinations were 

 made as in those in which the horses were vaccinated. In the winter of 1898- 

 99, Troster made serum injections in 17 batteries and 6 squadrons; each horse 

 receiving 50 grams of serum. The vaccinations caused an immediate pause 

 of 5 to 36 days in the progress of the epizootic, but the effect did not last and 

 was insufficient, since the epizootic was not extinguished. This brief protec- 

 tion, according to Troster, is only of value in the case of a mobilization, when 

 it may be desirable to protect a large number of horses from infection for a 

 a few days. All attempts to cure horses affected with contagious pneumonia 

 by vaccination with serum have failed. Further experiments were made by 

 Troster in 1899 on 58 horses with a larger quantity of serum (500 c.c, in two 

 portions, injected into the breast). The results of this experiment, by no means 

 extensive, seemed to Troster to justify the conclusion that the injection of 

 such large doses produced asufficient immunity, although the amount of serum 

 required was very difficult to obtain. In 1900 and 1901, he vaccinated 784 

 and 635 horses respectively with 100 to 150 grams of active blood-serum; 

 some of the vaccinations were effective (40 days immunity) and some were not. 

 In May, 1900, 518 horses in Dragoon Regiment No. 21 were vaccinated by 

 him and no effect was observed on the spread of the disease; 195 of the vacci- 

 nated horses developed extensive swellings and abscesses and some of them 

 were not fit for service for 14 days. Mieckley vaccinated 200 horses with 200 

 grams of serum each in the Beberbeck stud in 1900. The results were nega- 

 tive. In spite of the vaccination, 113 horses became affected with contagious 

 pneumonia, and of these 14 died. 



In the light of these experiences there can remain no doubt that serum 

 vaccination for contagious pneumonia is of no value. 



Cow Pox Vaccination of Man (Vaccination). — Since 1796 the lymph of 

 cow pox (vaccine) has been used for the protective vaccination of man against 

 smallpox (variola). Three kinds of vaccine are recognized: original, human, 

 and animal. The original vaccine is the lymph obtained from natural cow 

 pox, which was used in the beginning of vaccination; the human vaccine is 

 obtained from cow pox produced artificially on children, and the animal 

 vaccine is obtained from calves. At the present time, almost all vaccinations 



