ALCOHOLIC FERMENTS. 189 



The forms examined by Hansen, and which produce a 

 mycelium, must strictly be classed with the mould-fungi. 

 Since, however, their position amongst the moulds has not 

 yet been systematically determined, these species may, on 

 practical grounds, be described in this place. 



TORTJLA. 



The yeast-like forms which Pasteur figured and described 

 under the name Torula, are widely distributed and there- 

 fore not unfrequently occur in physiological analyses connected 

 with fermentation. They occur in both spherical and more 

 or less elongated forms, and are distinguished from the genus 

 Saccharomyces, as was first pointed out by Hansen, in that 

 they are unable to form endogenous spores. In most cases 

 they multiply only by budding, in some few cases also by the 

 formation of mycelium. 



Hansen has observed many different species, and has 

 described the following more in detail : 



The first occurs in wort, the cells being either single or in 

 colonies of a few cells. Some cells have a large vacuole in 

 the middle, and this sometimes contains a small strongly- 

 refractive particle. The size of the cells varies considerably 

 (1*5 to 4-5 /*). The species does not secrete invertase, and 

 causes a scarcely perceptible alcoholic fermentation in beer- 

 wort. 



The second species has, under the same conditions, larger 

 cells (3 to 8 /x) than the first ; they resemble the foregoing, 

 except that the contents of the cells grown in wort are often 

 very granular. 



The third species which, under the microscope, resembles 

 the last, produces under the same conditions as much as 0-88 

 per cent, by volume of alcohol ; it gives a distinct head with 

 evolution of carbonic acid, but it cannot invert cane-sugar. 



The fourth species (2 to 6/*) inverts cane-sugar and 

 produces a little more than 1 per cent, by volume of alcohol 



