SACCHAROMYCETES 549 



Rats are quite susceptible to inoculation with pus from lesions 

 or from cultures. The disease may follow an acute or a chronic course, 

 but the cutaneous nodules are not regularly produced in this animal 

 otherwise the lesions are fairly typical. In the acute disease the 

 animal usually dies within two weeks, frequently in consequence of a 

 degeneration of the parenchyma of the kidney. The organism may be 

 recovered from the blood stream or the kidneys a true sporotrichon 

 septicemia. In the chronic type of the disease the mold localizes and 

 results in the formation of multiple abscesses in the internal organs 

 and especially in the testes. Intraperitoneal injections usually lead 

 to the appearance of small nodules in the testes and internal organs 

 which may remain discrete or become confluent, with central necrosis 

 and suppuration. They resemble miliary tubercles superficially. 

 Microscopically the relatively large oval spores, but not the mycelia 

 are found. The disease appears to occur spontaneously in rats, espe- 

 cially the testicular type. 



The serum of cases of sporotrichosis frequently agglutinates the 

 spores of the organism (best obtained by grinding cultures to dryness 

 in a sterile mortar, then diluting with salt solution and filtering 

 through filter paper) in dilution from 1 to 200 even 1 to 1000. The 

 sera of normal individuals possesses no agglutinating power for the 

 organism. Actinomycotic serum may agglutinate with the organism 

 in dilutions as great as 1 to 50, suggesting common group agglutinins 

 for both organisms. Complement fixation is apparently not specific. 



SACCHAROMYCETES. 



The Saccharomycetes or yeasts are especially characterized by their 

 method of multiplication. Unlike the Bacteriacese, which reproduce 

 by transverse fission, the resulting cells being of equal size, the yeasts 

 reproduce by budding. A yeast cell about to reproduce sends out an 

 evagination or bud, which is first visible as a minute enlargement on 

 the surface of the parent organism. This gradually increases in size, 

 still maintaining an ovoid shape and remaining adherent by a small 

 isthmus until it reaches approximately the size of the original cell. 

 The isthmus then is broken, continuity between the two cells is inter- 

 rupted and the fully mature individual reproduces in like manner. 

 It is not uncommon to find budding in the daughter cell before it 

 severs its connection with the mother cell, if the environmental con- 

 ditions are favorable for rapid growth. Many yeasts form highly 



