462 A MANUAL OF BACTERIOLOGY 



tacese are also distinguished from the Bacteria by their larger size, 

 and in those forms in which endospores occur by the spores being 

 multiple and not single in each cell and by having a cellulose cell- 

 wall. From the Hyphomycetes, or moulds, the Saccharomycetaceae 

 are distinguished by being unicellular, and by the reproduction 

 being generally asexual. The Saccharomycetacese, however, are 

 probably much more nearly allied to the Hyphomycetes than are 

 the Bacteria, for many of the moulds have a stage in which the 

 mycelium (see next chapter) resembles an aggregation of yeast-cells, 

 and the yeasts in old cultures form films in which the cells become 

 much elongated, like those in the mycelium of a mould. Jorgensen 

 and others have attempted to show that some of the yeasts are 

 stages in the development of a fungus, but it cannot be said that 

 this has yet been satisfactorily demonstrated. 



Pathogenic Yeasts l 



Organisms apparently belonging to the Saccharomyce- 

 tacese and termed Blastomycetes have been isolated from 

 certain tumours, and have been regarded as having an 

 etiological significance in connection with malignant 

 disease. Sanfelice cultivated yeast forms from fermenting 

 fruits, which, on inoculation into guinea-pigs, produced 

 death in about a month with the formation of a tumour 

 at the seat of inoculation and embolic growths in the 

 spleen and liver. He also obtained a similar yeast from 

 an ox affected with carcinoma, which on subcutaneous 

 inoculation killed guinea-pigs in about two months, and 

 inoculated into the peritoneum in a month, with multiple 

 embolic growths in the lungs, spleen, and mesenteric glands. 

 A good deal of calcification was present in the growths, 

 from which fact Sanfelice named this yeast Saccharomyces 

 litogenes. Rabinowitch and also Foulerton 2 have found 

 that some of the ordinary yeasts give rise to tumour 

 formation on inoculation, especially in the rabbit. These 



1 See Le Count and Myers, Journ. of Infectious Diseases, vol. iv, 

 1907, p. 187. 



2 Journ. Path, and Bact., vol. vi, 1899, p. 37. 



