Classification of the Saccharomycetes. 81 



that the spores of the Smuts, in germinating, protrude a 

 thread from which spring tufts or clusters of sporidia ; these 

 unite with one another by short transverse processes, and 

 then give rise to sporidia or conidia of the third generation, 

 and these to even a fourth kind. Brefeld's theory is that 

 these successive generations of conidia do not merely 

 resemble Saccharomycetes, but are identical with them. He 

 cultivated the spores of many Ustilagineae in nutrient fluids, 

 and found that the conidia to which they gave rise were 

 in form and dimensions similar to those of the various 

 Yeast Fungi those of Ustilago antherarum being ovate ; of 

 U. Carbo, oblong-ovate ; of U. maydis, fusiform ; of U. be- 

 tonicce, cylindrical ; of U. Kuhniana, small and roundish ; 

 of U. cruenta, filiform ; and so on. Moreover, he cultivated 

 these sporidia in suitable media for numerous generations, 

 and found that they reproduced themselves, so long as 

 the conditions remained unaltered, with unfailing certainty 

 the whole year through. A pair of Smut spores was 

 induced to germinate, and the conidia which they produced 

 were transported, with due precautions, into a drop of 

 nutrient fluid, in which they continued to bud till the nutri- 

 ment was exhausted. A few of these were then removed 

 to another drop of the same fluid, and the process was 

 continued for nearly thirty times, extending over a space of 

 twelve months. The author considers that he has thus 

 proved that these conidia can propagate themselves inde- 

 finitely by budding, just like the cells of Saccharomyces, and 

 he asks, " If we had commenced this series of cultivations, 

 not with the Smut spores, but with the conidia which arise 

 from them, should we have been able to distinguish their 

 mode of growth from that of the yeast of beer ? " 



"As to the other morphological character of the Sacchar- 

 omycetes, the endogenous formation of the spores, Brefeld 



G 



