336 INFECTIVE DISEASES. 



Parke and Beebe, with a view to clearing up this question, made 

 cultures from three hundred and thirty healthy throats. They 

 found bacilli of three varieties : bacilli characteristic in growth 

 producing acid reaction in broth, but having no virulence; bacilh 

 not characteristic in growth producing an alkaline reaction in broth, 

 not virulent ; and bacilli producing acid reaction in broth and 

 virulent. The virulent characteristic diphtheria bacilli were found 

 in eight cases, non- virulent diphtheria bacilli in twenty-four, and 

 non-virulent false diphtheria bacUli in twenty-seven. They con- 

 cluded that the eight cases must have been in contact with diphtheria, 

 although the throats were healthy. With regard to the bacillus 

 in the twenty-four cases they regarded it as the true diphtheria 

 bacillus which had lost its virulence, and the bacillus found in the 

 twenty-seven cases showing differences in size and manner of staining 

 and the reaction produced in broth was properly designated pseudo- 

 diphtheria bacillus. 



Diphtheritic Diseases in Animals. 



There are diptheritic diseases of the lower animals which are in 

 some respects similar to, and, some observers maintain, identical 

 with, human diphtheria. 



In pigeons there is a disease accompanied with the formation of 

 false membranes associated with a bacillus described by Lbffler. 



Bacterium of Diphtheria of Pigeons (Bacillus colwnibarum, 

 Lbffler). — Short rods with rounded ends, mostly in irregular masses. 

 In plate-cultivations on nutrient gelatine they formed whitish patches 

 on the surface, and compact, ball-like masses when embedded in the 

 gelatine. They were also cultivated on blood serum and potatoes. 

 Subcutaneous inoculation of a pure- cultivation produced in pigeons 

 local inflammation and necrosis ; inoculation in the mucous mem- 

 brane of the mouth gave the appearances of the original disease. 

 Other animals were only locally affected, except mice, in which 

 characteristic symptoms and death resulted. They were isolated 

 from the diphtheritic exudations in pigeons, and in sections were 

 found in the vessels of the lungs and liver. 



A similar disease is known to attack fowls, and there are also 

 diseases with development of false membranes of the respiratory 

 passages in horses, cats and swine. Outbreaks of these diseases 

 have been said to occur in times of prevalence of diphtheria in 

 man, and their intercommunicability has been suggested. 



Dr. Turner supposes that diphtheria in man originates in diseases 



