THE YEASTS 631 



Other ferments by means of which they may split higher carbohydrates, 

 such as saccharose, maltose, and even starch, and prepare them for 

 action of the zymase. The manner in which this is accomplished, and 

 the by-products which are formed during the process, vary among 

 different species, and it is for this reason that the employment of pure 

 cultures is of such great importance in the wine and beer industries 

 where differences in flavor and other qualities may be directly dependent 

 upon the particular species of yeast employed for the fermentation. It 

 is due to the work chiefly of Pasteur ^ and of Hansen ^ that the beer and 

 wiae industries have been carried on along exact and scientific lines. 



As the incitants of disease in man, the yeasts have been much studied 

 since 1894, when Busse " reported a case of fatal, generalized yeast in- 

 fection, beginning from a tibial bone abscess. The microorganism which 

 was found in this case he named " Saccharomyces hominis." In morpho- 

 logical and biological characters it appeared to be a typical yeast, grew 

 readily upon most artificial media, and produced active fermentation in 

 sugars. Mycelia were not observed. When inoculated into animals, 

 this yeast proved pathogenic for mice and rats. A peculiarity of 

 Busse's culture, observed since then in the case of many pathogenic 

 yeasts, was the formation of gelatinous capsules, of varying thicknesses, 

 about the individual cells, developing with particular luxuriance in the 

 animal lesions. 



In 1896, Gilchrist ' described a peculiar skin disease, which he spoke 

 of as pseudo-lupus vulgaris, in the lesions of which he demonstrated a 

 large number of round, doubly-contoured bodies which, though differing 

 somewhat from Busse's saccharomyces, were unquestionably members 

 of, or closely related to, the family of blastomycetes. 



In the same year, Curtis,^ in France, isolated a similar form from a 

 myxoma of the leg. Ophiils" has described a number of fatal cases 

 occurring in Galifornia, which at first were wrongly interpreted as 

 protozoan in origin, but later were determined by him to be caused 

 by a species of blastomycetes. In a case observed by Zinsser ' simi- 

 lar microorganisms were isolated from an abscess of the back, which 



' Pasteur, " Etudes sur la bi&re," Paris, 1876. 



2 Hansen, " Prac. Studies in Fermentation," London, 1896. 



3 Bmse, Cent. f. Bakt., I, xvi, 1894, and Virch. Arcli., 140, 1895. 

 * Gilchrist, Bull. Johns Hopkins Hosp., vii, 1896. 



» CuHis, Ann. de I'inst. Pasteur, 10, 1896. 



« Ophuls, Jour. Exp. Med., 6, 1901. 



' Zinsser, Proc. N. Y. Patli. Soc, vii. 1907. 



