448 



THE MONILI^E AND OIDIA. 



measuring 5-14 a, are produced by the formation of numerous 

 septa in branches of the aerial hyphee (regarded as conidiophores 

 by Went), the individual cells thereafter becoming rounded and 

 beginning to detach themselves. Simultaneously there occurs an 

 additional reproduction, by the budding of the conidia, so that 



branched chains and groups of 

 conidia are produced (Fig. 204). 

 The conidia separate in a 

 peculiar manner, recalling to 

 some extent the isthmus forma- 

 tion observed in the Penicillia. 

 The conidia and that part of the 

 mycelium which is in direct con- 

 tact with the air, exhibit a pale 

 orange-yellow coloration, due to 

 a pigment similar to carotin. 

 The colouring- matter is mostly 

 distributed throughout the pro- 

 toplasm as barely visible fine 

 yellow drops, though sometimes 

 collected into visible globules. 

 In addition to the formation 

 of conidia, Went also observed 

 the production of small brown 

 structures, comparable with 

 young perithecia, but which 

 could not be induced to develop 

 completely. They commence 

 with a spiral convolution of 

 the hypha, which puts forth 

 numerous branches and grows 

 to a compact ball. The food 

 requirements of Monilia sito- 

 phila have been thoroughly 

 investigated by WENT (V.). The 

 fungus is very rich in enzymes, 

 none of the more important 

 ones being lacking, whilst even 

 several of the rarer members of the group are present. Conse- 

 quently, the organism was rightly looked on as omnivorous ; and 

 it is even able to thrive on filter-paper. It is almost insensitive 

 to the general reaction of the nutrient medium, a high degree of 

 acidity (10 c.c. of decinormal sulphuric acid per 100 c.c. of nutrient 

 solution) alone being able to arrest development, whilst on the 

 other hand large quantities of alkali have no important influence. 

 The species grows vigorously even out of contact with air ; and it 

 is only when oxygen is completely excluded that it languishes. 

 Small quantities of alcohol are formed in both anaerobic and 



FIG. 204. Monilia sitophila. 



Aerial hyphae (couidiopliores) with bud- 

 ding yeast conidia. Magn. 220. 

 (After Went.) 



