122 YEAST 



IV 



Leeuwenhoek speaks, though the constancy of 

 their arrangement in sixes existed only in the 

 worthy Dutchman s imagination. 



It was very soon made out that these yeast 

 organisms, to which Turpin gave the name of 

 Torula ccrcvisicu, were more nearly allied to the 

 lower Fungi than to anything else. Indeed 

 Turpin, and subsequently Berkeley and Hoffmann, 

 believed that they had traced the development of 

 the Torula into the well-known and very common 

 mould the Penicillium glaucum. Other observers 

 have not succeeded in verifying these statements ; 

 and my own observations lead me to believe, that 

 while the connection between Torula and the 

 moulds is a very close one, it is of a different 

 nature from that which has been supposed. I 

 have never been able to trace the development of 

 Torula into a true mould ; but it is quite easy to 

 prove that species of true mould, such as Pcni- 

 cillium, when sown in an appropriate nidus, such 

 as a solution of tartrate of ammonia and yeast- 

 ash, in water, with or without sugar, give rise to 

 Torulcc, similar in all respects to T. ccrcvisiw, 

 except that they are, on the average, smaller. 

 Moreover, Bail has observed the development of a 

 Torula larger than T. ccrcvisicc, from a Mucor, a 

 mould allied to Penicillium. 



It follows, therefore, that the Torulcc, or 

 organisms of yeast, are veritable plants ; and con 

 clusive experiments have proved that the power 



