﻿416 STRONG. 



notwithstanding the experiments of Kraus. The bacteriologic diagnosis 

 in cases of cholera in the late stages of the disease was sometimes very 

 difficult, and a careful study of the faeces by plate cultures, prepared 

 both directly from the stool and from the surface of peptone solution 

 cultures previously inoculated with large amounts (several cubic centi- 

 meters) of the stool, is sometimes necessary in such eases before the 

 organism is isolated. Frequently, an examination of the agglutinative 

 and bactericidal reaction of the blood serum of the patient in these 

 subacute cases will render further assistance in reaching a diagnosis, 

 particularly if the reactions are positive. 



PREPARATION AND FURNISHING OP CHOLERA IMMUNE SERA FOR DIAGNOSIS. 



In addition to the preparation of fresh cholera immune sera for diag- 

 nostic purposes in the central laboratory, such sera were also prepared 

 and furnished to various physicians and institutions in the city and 

 in certain of the provinces for use in the bacteriologic diagnosis of the 

 disease. jSTo dried cholera serum was issued, it having been found 

 practicable and more desirable to furnish a fresh serum by means of 

 which not only an agglutinative test, but also a bacteriolytic one under 

 the microscope according to the method of Bordet could be performed. 

 It was found that a single intravenous inoculation of a rabbit with the 

 immunizing substances extracted from about 60 to 70 milligrams of a 

 virulent cholera organism would furnish a serum of sufficient value 

 for all practical purposes in diagnosis. The animal may be bled to 

 death on the sixth or seventh day after such an inoculation and the 

 serum separated. Such sera almost invariably show an agglutinative 

 value of from 1 : 1,000 to 1 : 2,000 ; values as low as 1 : 800 have been 

 obtained only in exceptional cases. The bactericidal almost invariably 

 exceeds the agglutinative value of the serum prepared in this manner, 

 the different sera reacting bactericidally in amounts of from 0.2 to 0.05 

 milligram. 



After the serum had been standardized it was sealed in test tubes 

 and was ready for delivery. Fresh serum produced by this method was 

 kept on hand throughout the epidemic. 



PROPHYLACTIC INOCULATIONS. 



The laboratory in addition to the diagnostic work was particularly 

 occupied in the preparation and standardization of cholera prophylactic 

 and in the performance of the protective inoculations against the disease 

 in certain badly infected cholera districts in Manila and the provinces. 



The prophylactic prepared and employed consisted of the immuniz- 

 ing substances extracted from the cholera spirillum and suspended in 



