88 USE OF MUCOEE^ IN THE SPIRIT INDUSTRY. 



occurs in those on sugar-agar, thus affording here a new and 

 beautiful example of the influence of the conditions of nutrition 

 on development. The mycelium produces an abundance of 

 gemuiEB, of different sizes and shapes, either globular (fi'om lo 

 to lo > /x in diameter) or oval. They are colourless, or pale yellow 

 to light brown, and have a very thick, smooth, colourless mem- 

 brane. It is solely in the form of these resting cells that the 

 fungus appears in Chinese yeast, to which, as Calmette has 

 shown, it gains access from the rice husks and rice straw. This 

 explains why, in many places, the manufacturers of Chinese 

 yeast consider it indispensable to press a few moistened rice 

 husks into each of the fresh, pasty yeast cakes. As soon as the 



Fig. ii8. — ^lucor Ronxii. 



Sympodial branched sporangiophore, 

 from a 7-days old culture on sugar-agar. 

 ilagn. about 160. (After Wc/niier.) 



Fig 119. — Mucor Rouxii. 



Sporangium almost entirely empty. 

 Part of the wall still hanging in large 

 shreds on the sporangiophore. In front 

 of the globular columella are still lying 

 three spores. From a culture on rice. 

 Magn. about 230. (After Wehmer.) 



gemmae arrive in a suitable nutrient medium they put forth 

 germinating tubes and develop into mycelia. Up to the present 

 no zygospores or yeast-like budding cells have been observed in 

 this fungus. When grown on solid media (steamed rice in par- 

 ticular) the mycelium gradually assumes a highly characteristic 

 orange colour due to golden yellow drops (oil ?) appearing in 

 the cell, but only at room tempei'ature, though not at 40° C. 

 The optimum temperature for the development of the mycelium 

 lies between 35° and 40° C. According to Calmette, a tempera- 

 ture of 75° C. kills the organism within half-an-hour, and 80° C. 

 is fatal in 1 5 minutes. 



The same observer states that the diastatic enzyme produced 

 by Mucor Rouxii exerts its most powerful effects at 35 to 38° C, 

 and is destroyed on being warmed to 72° C. According to 

 BoiDiN and Rolants (I.), the sugar thus formed from the starch 

 is glucose. Like Itevulose, saccharose, maltose, and lactose, this 



