332 A MANUAL OF BACTERIOLOGY 



found in milk and cheese (see section on " Milk "), and 

 also in the lower animals, e.g. in the throats of cats 

 (Savage), and of fowls and pigeons (Hewlett). 



Toxins. Diphtheria toxin has not been obtained in 'a 

 state of purity and its exact chemical nature is unknown. 

 Loffler by precipitating broth cultures with alcohol 

 obtained a white toxic substance which he classed among 

 the enzymes. 



Roux and Yersin found that the toxin was precipitated 

 from filtered broth cultures by absolute alcohol, and also 

 by saturation with calcium chloride. They considered 

 the toxin to be an enzyme. 



From the blood and spleen of cases of diphtheria Sidney 

 Martin isolated albumoses (chiefly deutero-albumose) and 

 an organic acid, but no basic body. Injected subcu- 

 taneously the albumose produces oedema and irregularity 

 of temperature ; in larger doses depression of temperature 

 with paralysis and coma. Small multiple sub -lethal 

 doses may give rise to some fever, followed by paralysis 

 of the hind legs in rabbits, with weakness and loss of 

 weight. Post-mortem, the heart is fatty and the nerves 

 have undergone degeneration. The organic acid is also 

 a nerve poison, but is not so toxic as the albumose. From 

 diphtheritic membrane, extracted with a 10 per cent, salt 

 solution, only traces of albumose and organic acid were 

 obtained, but the extract was highly toxic, producing 

 fever and paralysis. Sidney Martin suggests that a 

 substance of the nature of a ferment may be present and 

 that the ferment in the membrane on absorption may 

 perhaps form the albumose in the body. From cultures of 

 the diphtheria bacillus in alkali -albumin, albumose and 

 organic acid, with similar actions to those isolated from 

 the body, were obtained. 



Brieger and Frankel (1890) were unable to find any 

 basic substance in cultures, and concluded that the toxic 



