THE OKIOIN or THK SAC'CHAIIO.MVCKTKS. 107 



alone. On tho othor hurnl, it ilj«l a guoj deal of luihchief at 

 first ill the stmly of yeasts. 



The ohvious ()l)jectioii that the lack of reliaVile methods 

 of jmre eultuie i-oukl also luiliUite against the certiiiiity of 

 Tulasue's results, can at once ho disposed of hy the fact that 

 this authority workt-d with comparatively large fungi; and, 

 moreover, a study of his wcuks will very soon induce th»* conviction 

 that such iloul)ts are incapable of shaking the reliability of his 

 discoveries. Furthermore, his determinations in connection 

 with the progress of development — which were mainly based on 

 microscopical researches — were afterwards confirmed bv the 

 cultures prepared by A. ile Hary and others. Tlie case was, 

 however, dilferent as soon as a crowd of imitators began 

 attempts to prove the e.xistenci' «jf similar pli-oniorphism in the 

 less easily examined lower and lowest fungi. Whereas, in the 

 case of the fungi examined by Tulasne— for instance a sclero- 

 tium of (.'farin'ji.'i purpurea — it was ea.sy to select an individual 

 and test its development, it became necessiiry, with the micro- 

 scopically small fungi, to start with a multiplicity of individuals, 

 e.ij. a sample of yeast, owing to the absence of any methoil 

 of pure culture. The detectit)n of a small percentage of germs 

 of other small fungi, <'.(/. a few conidia of a mould fungus, was 

 not such an ea.sy matter, though the sjime nece>.siirilY made 

 their pre.sence felt and even a.ssumed a predominating j)osi- 

 tion when the environment underwent a change in theii- favour. 

 Either in ignorance of, 01 stubboinly misunderstanding, this 

 stiite of affairs, Bcchamp, in iSyijput forward the assumption 

 that yeast cells could be developed from acetic bacteria. A 

 year later, TuKm. (II.) announced having maile the .^ime 

 observation with spores of P'tiirilliinii. C'tmver.selv. according 

 to Dl'val (I.), y«ist cells were assumed wipable of undergoing 

 conversion into lactic acid bacteria. More extensive fallacies 

 were advanced in 1875 by Kuiu.v (1.), giving renewed vitalitv 

 to the reports of ruuciiCT (I.) and lUii,, according to whoili 

 yeast cells are able to change to Mu.;„\ I'mirillium, Aa/Hrt/i/hi.", 

 \-c. (ireater success was attained by II. HokkMan (III.), who 

 even obtiined a prize from the Paiis Academy in 1870 foi- his 

 conversions. Foi- " st^iying power," however, the palm must be 

 awarded to H. IIai.i.ikk (II.), who still continued to uphold, in 

 1896, the hypothesis which had been relegated bvA.de Harv 

 to the "chronicpio scandaleuse " of .science more than fifteen 

 yejirs ejirlier. 



One extenuating circumstance to be considered in jwissing 

 judgment on most of the above-named, is the fiuctuations of 

 meaning sustained by the term yeast in the cour-se of time. A 

 backward glance on this {uiint is therefore nece.ssjiry. even on 

 this ground alone. Apart from the vague terminology which 

 permitted (5$ 13) every fermentative agent, even the fi.ssion fungi. 



