26 CONDITIONS MODIFYING [CH. n 



Ohlmacher (1902) claimed to have changed typical B. 

 diphtheriae into Hoffmann's bacillus by 48 hours subcutaneous 

 growth in a rat previously immunised. 



The "solid-staining" type of B. diphtheriae has been 

 inoculated into a guineapig and the "granular" type has 

 been recovered subsequently from the site of the inoculation 

 (Denny, 1903). 



Such a method is not invariably successful. For example, 

 Baldwin (1910) grew the human type of tubercle bacillus in 

 the living tissues of the cow for nineteen months, in the hope 

 of modifying its characters to those of the bovine type, but 

 without success. 



(e) During the course of a disease the organism responsible 

 is not infrequently observed to undergo modification with 

 respect to one or another character. Thus in diphtheria, as 

 convalescence is reached, the "granular" forms of the bacillus 

 give place to "solid-staining" types (Gorham, 1901). 



In the chronic stages of cerebrospinal fever the meningo- 

 coccus isolated from the spinal fluid is found to have lost in 

 some cases its power to ferment dextrose (Connal, 1910). 

 Ark wright (1909) found bacillary forms of the meningococcus 

 in the spinal fluid in several cases of cerebrospinal meningitis. 



Adami, Abbott and Nicholson (1899) isolated from the 

 ascitic fluid in cases of cirrhosis, strains of B. coli (already 

 described, vide p. 25) possessing unusual morphological, 

 cultural and fermenting characters. Similar variants of B. coli 

 were obtained from an inflamed gall-bladder. 



Foa (1890) injected the pneumococcus into a rabbit and 

 after its death isolated strains from the lung and from the 

 spinal fluid which produced lesions of two distinct types when 

 injected into other rabbits. He proved by experiment that 

 the difference between the two strains was due to differences 

 in the amount of oxygen available for them in the lung and in 

 the spinal canal. 



Rosenow (1912-13) describes a certain streptococcus, 

 isolated from cases of epidemic sore throat which exhibited 

 unusual and distinctive morphological and cultural characters. 

 "The strains isolated from the peritoneal exudate and blood 



