EMPLOYMENT OF BLOOD SERUM 261 



in different individuals is of common occurrence. A wide variety 

 of antisera has been employed, but no attempt has been made to stand- 

 ardize the different sera. In many instances the cases treated were 

 especially selected and moribund cases excluded. The result is that much 

 of the existing statistical data is unreliable. Yersin, Calmette and Borrel 

 were the first to show that the serum of an animal immunized to bacillus 

 pestis has protective qualities and Yersin is credited with the production 

 of anti-plague horse serum. This serum was prepared by immunization 

 of horses first with dead and subsequently with living bacilli. Tavell's 

 serum was prepared on the same principle, but Hata and also Kraus 

 immunized their animals with dead bacilli alone and claim that these 

 sera compare favorably with sera produced by the injection of living 

 bacilli. The use of dead bacilli minimizes the danger of laboratory in- 

 fections. Soon after the discovery of the nucleoproteins by Ferrannini, 

 Galeotti and Lustig employed nucleoproteins from plague bacilli as 

 antigen for the production of anti-plague serum. For this purpose the 

 bacilli were broken down in i per cent. KOH solution and the nucleo- 

 proteins precipitated by the addition of acetic acid and then suspended 

 in salt solution. Rowland also used a similar antigen, and others have 

 employed a variety of extracts as antigens. 



The serum at present most commonly used is obtained from horses 

 after repeated intravenous injections of killed cultures sometimes fol- 

 lowed by living organisms. Experimentally the sera show considerable 

 strength in protecting animals against infection and exhibit specific 

 bacteriolytic, bacteriotropic, agglutinative and antitoxic qualities. The 

 antitoxic titer is usually very low. According to Kraus, Yersin's serum 

 is not any better than the sera prepared with dead bacilli or nucleo- 

 proteins. Yersin used his serum in twenty-six cases during the epi- 

 demics of 1896 in Canton and Amoy, China, with a mortality of 7.6 

 per cent., while the mortality in cases not treated with serum reached 

 80 per cent, to 90 per cent. In 1897 141 cases were treated in Bombay 

 and Cutch-Mandir with a mortality of 49 per cent. Of 685 cases not 

 treated 80 per cent. died. In 1898 thirty-three cases were treated in 

 Anam with Yersin's serum. The death rate among non-treated cases 

 was 100 per cent, but was 42 per cent, among the serum-treated cases. 

 It was found that the serum was entirely inefficient in cases with the 

 pneumonic form of the disease. The German Commission at Bombay 

 claimed that the low mortality (50 per cent.) o>f serum-treated cases was 

 due to the selection of mild cases or cases arriving at the hospitals 

 during the first or second day of their illness. Clemon also failed to 

 obtain results in his fifty cases in which he injected as much as 60 c.c. 

 of the Yersin serum. The Indian Plague Commission did not report 

 favorably on Yersin's serum. Calmette and Salimbeni obtained very 

 good results with serotherapy in Oporto, Portugal ; of 142 treated cases 

 twenty-one died, while of seventy-two not treated forty-six died. Kos- 

 sel and Frosch and others studied this epidemic and found it to be of 

 a mild type. During the Manchurian campaign serum treatments 

 were entirely inefficient. Choksy injected large doses (100 c.c) 



