300 INTRODUCTION TO THE STUDY OF FUNGI 



surrounds itself with a proper membrane, and becomes a spore, 

 which is capable of budding, like the vegetative cells. 



Whether the so-called species of Saccharomyces are autono- 

 mous, or only stages in the development of some higher forms, 

 need not be discussed here. "Brefeld considers that the 

 conidia of various species of Ustilagineae exactly resemble in 

 mode of growth many of the forms of the so-called Saccharomyces. 

 It is well known that the spores of the smuts, in germinating, 

 protrude a thread, from which spring tufts, or clusters, of 

 sporules; these unite with one another by short transverse 

 processes, and then give rise to sporules, 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 Saccharomyces, 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 species 

 of yeast Fungi — those of one being ovate, of another oblong- 

 ovate, of another fusiform, of another cylindrical, of another 

 small and roundish, and of another filiform, and so on. More- 

 over, he cultivated these sporules 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 in- 

 duced 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 indefinitely 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 ? " 1 



1 Synopsis of the Bacteria and Yeast Fungi, by W. B. Grove, B.A. (1884), 

 p. 81. 



