BARBER: HEREDITY IN CERTAIN MICRO-ORGANISMS. 7 



W. Henneberg ( 1903) found giant cells in each of two types 

 of distillery yeasts, the large size of which was transmitted to 

 daughter-cells budding from them. The tendency to store 

 glycogen was also found to be hereditary in these types. 



W. W. Lepeschkin (1903) found in Schizosaccharomyces 

 pombe and S. melacei cells which grew out in the form of my- 

 celia, instead of dividing in the usual manner of the genus. 

 Some of these cells were isolated and found to reproduce the 

 new characteristic. When grown under conditions favoring 

 endogenous spore formation, these cells produced an oidium- 

 like growth, and spore formation was rarely observed. When 

 spores were produced and made to germinate, they reproduced 

 the elongated type of growth peculiar to the new race. The 

 author thinks the new form an example of mutation or 

 heterogenesis. 



Comparatively little has been done in selection experiments 

 on bacteria where the isolation of single cells is involved. 



H. W. Conn (1899) describes a culture of bacteria, isolated 

 by him from milk, which shows great variability, not due, 

 apparently, to the immediate environment. The color of 

 colonies varied from a milk white to deep orange, and from 

 colonies rapidly liquefying the medium to non-liquefying 

 colonies. By selection of colonies in plate cultures made 

 from a pure culture he obtained pure white and pure orange, 

 as well as liquefying and non-liquefying strains. 



A. Meyer (1901) found that the proportion of branched 

 cells in Bacillus cohserans is greater in that part of gelatin 

 plates where branched cells were sown ; and he concludes 

 that there is a tendency for this peculiarity to be transmitted. 

 He is of the opinion that bacteria are descended from fungi 

 with branched mycelia, and that occasional branching is to 

 be regarded as atavism, not as the formation of a new 

 character. 



W. W. Lepeschkin (1904) found in Bacillus herestntwii cer- 

 tain branched individuals and also small non-septate mycelia. 

 The offspring of isolated branched cells exhibited five to 

 fifteen per cent, of branched cells after only twenty to fifty 

 offspring had been formed, while the offspring of the un- 

 branched showed none until after many generations of cells 



