ANIMAL INOCULATIONS 197 



Taxonomy. On the basis of these rather variable cultural char- 

 acters a number of different species of pathogenic Sporotrichum have 

 been described. Buschke and Langer recognized thirteen. It would 

 seem, however, that the differences upon which these species were 

 made are well within the limits of variability of a single strain. 

 Greatest stress has been placed upon the differentiation between the 

 American species, Syorotrichum Schenckii, and the variety described 

 in Europe as S. Beurmanni. These have been separated mainly on 

 the ground of pigment formation, S. Schenckii being light and S. 

 Beurmanni dark; on the degree of spore formation, ;S. Schenckii 

 forming fewer lateral conidia; and on sugar fermentations, S. 

 Schenckii producing acid from lactose, not sucrose, whereas S. Beur- 

 manni is said to ferment sucrose but not lactose. Davis,* however, 

 has shown that both pigment formation and spore formation are too 

 variable to be used for differentiation because it depends more on 

 the nature of the medium and rapidity of transfer than on the strain. 

 Meyer ^ similarly found that sugar fermentations are highly variable. 

 It would seem, therefore, that although different strains may appear 

 somewhat unlike, there is no valid reason for recognizing more than 

 one of these species, S. Schenckii. 



Animal Inoculations. Although various laboratory animals are 

 susceptible to infection, rats are particularly so. In addition to mak- 

 ing cultures, inoculation into a male white rat is a procedure of con- 

 siderable diagnostic value. The inoculation should be made into 

 the peritoneal cavity. There occurs a generalized peritonitis with 

 minute nodules on all the peritoneal surfaces, and in addition a very 

 pronounced inflammation of the testis, which may be determined 

 without sacrificing the rat. Unlike human lesions, those in the rat 

 contain the typical cigar-shaped cells in great abundance, and these 

 may be found readily in Gram-stained smears. 



The agglutination reaction with spores of Sporotrichum has been 

 discussed in Chapter VI. This reaction, introduced by Widal and 

 his coworkers, is of considerable diagnostic value; though cross re- 

 actions occur with thrush and actinomycosis, these diseases are not 

 likely to be confused with sporotrichosis. The best diagnostic pro- 

 cedure is the isolation of the organism in culture, or by inoculation 

 of a rat. Davis ^ was unable to differentiate various strains of Sporo- 

 trichum, including some of equine origin, by means of agglutination 

 reactions. Cutaneous reactions are positive but are considered less 

 specific than agglutination. Moore and Davis ^ got no reaction with 

 an extract of the organism of blastomycosis in a case of sporotricho- 

 sis. 



