58 CRYSTALS AND LIVING UNITS 



it was not till 1840 that the development of Torulae into Fungi was 

 traced. 



The particular forms assumed by the outgrowths from ger- 

 minating Torula corpuscles seem subject to much natural varia- 

 tion. Thus Trecul found that on exposure to the air the cells of 

 beer yeast grew partly into the form of Mycoderma cerevisiae, and 

 partly into that of a large Penicillium. He became convinced, 

 therefore, that the view originally advocated by Turpin is correct, 

 viz. that Mycoderma and PenicilUum are simply two forms which 

 may be assumed by germinating beer Torul2e. Nay, more, the 

 Mycoderma itself is observed to be most changeable in its form, 

 as the qualities of the fluid in which it grows alter ; and an already 

 growing Mycoderma is said to be capable of taking on the mode 

 of growth characteristic of Penicillium.' 



Commonly, however, when beer-wort is exposed to the air and 

 is not disturbed, Mycoderma begins to develop in about forty-eight 

 hours — though curiously enough its appearance may be delayed 

 for a fortnight or more by agitating the liquid two or three times 

 daily. It commences in the form of the minutest specks, which 

 gradually enlarge into ellipsoid corpuscles ; these give birth after 

 a time to a little bud at one extremity, and this grows into a 

 corpuscle which in its turn produces another. Lateral buds are 

 also produced, and after a time this mode of growth results in 

 elegant, much-branched tufts, which vary in form as alterations 

 in the medium proceed. But when beer- wort containing the 

 Mycoderma is poured into a bottle (so as to fill it) and this is 

 tightly stoppered, the plant ceases to grow in this form and gives 

 place to an abundance of Torulae — these being partly derived from 

 portions of the pre-existing Mycoderma. The Torula form, and 

 'discontinuous' mode of growth, is that which seems to be in- 

 variably engendered when the liquid becomes more or less charged 

 with COj and alcohol, and when the pressure increases. Boiled 

 beer- wort in a sealed vessel also produces Torulse (see Note, p. 153) 

 where there has been no pre-existing Mycoderma ; and, according 

 to Trecul, the Torulas, thus engendered, after exposure to the air 

 will also gradually assume the form of Mycoderma. 



We have thus endeavoured to show that if, in accordance with 



" See "Compt. Rend." t. 67, p. 1164. This development of Mycoderma into 

 forms resembling Penicillium glaucum, was observed by Turpin in 1840, by the 

 Rev. M. J. Berkeley in 1855 (from porter yeast), and subsequently, by Poucliet, 

 in beer yeast and in that from cider. 



