406 MICRO-ORGANISMS AND FERMENTATION. 



first observed by K. Amthor. One race produces more volatile 

 acid or more alcohol and glycerine than another. 



Miiller-Thurgau subjected seven different races to exami- 

 nation. They produced from 2-5 to 3-8 per cent, by weight 

 of alcohol in grape juice ; two races gave as much as 6 per 

 cent. Schander found cells of different shape and size in the 

 apiculatus yeasts that he examined, some short, thick, and 

 lemon-shaped, and others thin, elongated, and of a less distinct 

 lemon-shape. Holding's different species exhibited slight 

 physiological differences, and Will, who isolated a few species 

 from wort, showed that they can be distinguished by the 

 different aroma produced in wort. 



P. Lindner has described Sacch. apic., var. parasitic/us, 

 living on wood-lice. One end of the cell is often drawn out 

 to a point which penetrates their eggs and then forms a bud. 

 In this way the eggs infect the mother insect, and the yeast 

 is distributed by their offspring. They cannot be cultivated 

 in fruit juice or in artificial nutritive liquids. We are dealing 

 here with an obligatory parasite. 



The question how far 8. apic. is capable of forming endo- 

 genous spores was thrashed out long ago ; in 1894 it was 

 answered in the affirmative by Beijerinck. He stated : 

 " If a convincing proof is required of the property of spore- 

 formation, it is only necessary to isolate this yeast when 

 conveyed by air or dry dust on to fruit. In this way cultures 

 are occasionally met with, containing individual cells swollen 

 to asci, with from four to six ascospores." He did not, how- 

 ever, observe a germination of the spores. 



P. Lindner examined cells of S. apic. from blossoms of 

 Eobinia Pseudacacia in streak-cultures with wort contained 

 in moist chambers, and found a development of spores in the 

 culture. They show a distinct wall and a granulated pro- 

 toplasm. According to the picture, each cell contains only 

 one spore. Again, no germination of spores was observed. 

 Descendants of this growth showed no tendency to form 

 spores. 



Influenced by these experiments, Lindner classed the 

 apiculatus yeast as a new genus, which he named Hansenia. 

 A. Rohling worked with pure cultures of races derived 





