482 INFECTION AND RESISTANCE 



its curative action to the fact that in the presence of this serum active 

 phagocytosis takes place. 



Dean, 80 in 1906, also claimed to have produced strongly antitoxic 

 plague sera by treating horses with nitrates from 8 to 10 weeks old 

 bouillon cultures. He claims that 1 c. c. of his serum will neutralize 

 150 or 450 minimal lethal doses of the plague poison according to 

 whether one measures the M L D by death in 48 hours or in 4 days. 

 Rowland 81 also has produced a serum by the immunization of ani- 

 mals with the "toxins" produced by his sulphate process. Rowland 

 has apparently utilized the idea previously advanced by Lustig of 

 immunizing with "nucleoproteins" derived from the plague bacillus 

 instead of with the whole bacteria. Lustig's 82 method consisted of 

 washing up agar cultures of plague bacilli in 1 per cent, sodium 

 hydrate solution, precipitating with ascitic acid, taking up the pre- 

 cipitate in an indifferent fluid and injecting it into horses. The 

 serum produced by Lustig's method was used in Bombay, and is re- 

 ported by Hahn as effective in milder cases, but without action in 

 the more severe ones. There was but slight difference in the latter 

 type between the treated and the untreated cases. 



Rowland's 83 method consisted in the treatment of the moist 

 bacteria with enough anhydrous sulphate of soda to combine with 

 all the water present, freezing and thawing the mixture and filtering 

 off the bacterial deposit at 37 C. Subsequently he extracted this 

 bacterial mass with water. The extract so obtained was fatal to 

 rats in quantities of 0.05 to 0.1 mg., killing them in 18 hours. In 

 his experiments doses of 0.001 to 0.01 afforded protection, the last- 

 named quantity reducing the mortality after inoculation of fatal 

 doses from 80 per cent, to 10 per cent. 



The sera produced by the immunization of horses with these 

 supposed nucleoproteids are taken to be antitoxic in nature by Row- 

 land himself and by MacKonky. They were used in the treatment of 

 plague cases in the epidemics of 1908 and 1911 by the Maratha Hos- 

 pital in Bombay, and reported upon by the Indian Plague Commis- 

 sion on the basis of observations made by Dr. Choksy. The cases in 

 this series were controlled, as were those treated by the Yersin serum, 

 by blood culture. Here the results were not striking 68.40 per 

 cent, of the serum-treated cases died, while 77.60 per cent, of the 

 controls died. 



' Altogether we cannot draw any definite conclusions as to the 

 value of the serum treatment in plague. On the whole it does appear 



80 Dean. Cited from MacKonky, Journ. of Hyg-, Vol. 12, Plague Suppl. 

 II, 1912, p. 402. 

 , 81 Rowland. Journ. of Hyg., Vol. 11, Plague Suppl. I, pp. 11-19. 



82 Lustig. "Monograph Sierotrapia e Vaccin Prev. Control la Peste,* 

 Turin, 1899 ; cited from Kolle and Martini, loc. cit. 



83 Rowland. Journ. of Hyg., Vol. 10, p. 536. 



