520 APPLICATION OF METHODS OF BACTERIOLOGY 



type of organism in dilutions of 1 : 50. On the other hand, 

 the serum of an animal immunized with the Flexner type 

 of organism will agglutinate that type of organism in high 

 dilutions, say 1 : 10,000, while the other two types of the 

 organism will be agglutinated only in dilutions of 1 : 100. 

 The serum of an animal immunized with the Hiss-Russell 

 type of organism will agglutinate that type of organism 

 in dilutions, say of 1 : 1000, while the Harris type is agglu- 

 tinated only in dilutions of 1 : 100, and the Shiga type in 

 dilutions of 1 : 20. 



Protective Inoculation. — By the repeated inoculation of 

 animals with cultures of this organism, killed either by heat 

 or by chemicals, it has been found possible to protect them 

 against otherwise fatal doses of the living virulent organism. 

 When treated in this way, the goat supplies a serum that 

 exhibits not only an agglutinating power over the living 

 bacilli, but possesses both protective and curative properties 

 when injected into other susceptible animals. 



During 1898-1899 Shiga* employed a protective serum, 

 made after the foregoing principles, in the treatment of 

 dysentery in human beings. During the period mentioned 

 he treated 266 cases, and had a death-rate of 9.6 per cent.; 

 while for 1736 cases occurring at the same time and in the 

 same locality, but not so treated, there was a death rate 

 of 34.7 per cent.^ 



Holt' summarizes the results obtained in the treatment 



' See The Epidemic Dysentery of the Past Twenty Years in Japan, by 

 Stuart Eldridge, M.D., U. S. Marine-Hospital Service, Public Health 

 Reports, 1900, xv. No. 1, 1-11. 



2 The foregoing sketch is compiled from : 



Shiga, Ueber den Dysenterie-bacillus (Bacillus dysenteriae) , Centralblatt 

 fiir Bakteriologie und Parasitenkunde, 1898, Abt. i, Bd. xxiv, Nos. 22, 23, 24. 



Flexner, On the Etiology of Tropical Dysentery, Philadelphia Medical 

 Journal, September 1, 1900. 



3 Studies from the Rockefeller Institute for Medical Research, 1904, vol. ii. 



