HISTORICAL, DELIMITATION, DERIVATION. 387 



from the Torulacea, many of them, so far as is known, having 

 many points of resemblance, morphologically, with the Torulacett, 

 although they have not been studied with any thoroughness. 

 Pigmentation cannot, at least, be regarded as a sufficient reason 

 for their separation, since the researches of Kossowicz (I.), con- 

 firmed by R. SQUANDER (I.), show that several of the Saccha.- 

 romycetes which are colourless under ordinary conditions develop 

 a red colouring-matter in certain circumstances, notably in 

 presence of salts of magnesium. On the other hand, some of 

 the typical forms of Torula occasionally assume a pink coloration 

 only under certain conditions of growth, such as in films on 

 nutrient liquids and in slant colonies. Pigmentation is by no 

 means a constant feature. Nevertheless, the so-called pink yeasts 

 and other coloured budding fungi will, for practical reasons, be 

 dealt with separately in the present chapter under 301. 



The opinion that the Torulacece are only stages in the 

 development of other fungi has already been expressed by HANSEN 

 (LIU.). It is known that the conidia of certain Ustilaginece 

 (see p. 109, vol. ii.) are able to maintain an independent existence, 

 by budding, in suitable nutrient solution?. Budding cells are 

 also met with in various groups of fungi; and possibly similar 

 biological conditions may give rise to the same or similar external 

 phenomena. The Torula group is not a natural one, and is 

 merely of a temporary character. 



E. KLEIN and M. GORDON (I.) claimed to have traced the 

 origin "of a pathogenic pink yeast to Puccinia suaveolens. On 

 the other hand, R. MEISSNER (II.), in comparing his six species 

 of mucinous yeasts (see p. 177, vol. ii.) with the budding cells of 

 Exoascus spores, with which they seemed to have some con- 

 nection, established an important point of difference between 

 them and the budding cells of Exoascus deformans. It may also be 

 remarked that LAURENT (VIII.) has stated that the budding forms 

 of Cladosporium kerbarum (seep. 378, vol. ii.) are transformed into 

 a pink yeast by insolation. In addition, WINKLER (II.) claimed 

 that Mucor spores, under certain culture methods, furnished " yeast 

 cells " that were asporogenic, for which reason he proposed to 

 group them, pro tern., with the Torulacece. Agreeable though 

 the idea may be that these organisms are merely budding forms 

 of the conidia or spores of higher fungi, reports in this connection 

 require to be very critically examined. 



In treating of the asporogenic budding fungi mentioned in the 

 literature, under the generic name of Tonda, or more generally 

 referred to as yeast, white yeast, &c., it is often difficult, nay 

 impossible, to decide if they belong to the group under considera- 

 tion. On the one hand it must be remembered that the name 

 Torula has been, and is still, applied at different times to very 

 different organisms. Originally implying Hyphomycetes with 

 conidia arranged in wreaths, with simple or branched chains, 



