i 9 o8] HASSELBRINC— ASSIMILATION OF PENICILLIUM 185 



TABLE X 



Ethyl acetate is easily soluble in water and forms a suitable source 

 of carbon for fungi. It is poisonous, however, in comparatively low 

 concentrations. The fungi in this medium grew for a time and then 

 ceased growing, owing to the accumulation of acetic acid in the cul- 

 tures. The addition of mineral acids had no very evident effect on 

 the growth of the mold, but seemed to depress rather than increase the 

 yield. It is important to note that the cultures containing alcohol in 

 addition to ethyl acetate {table X, col. Ill) gave a yield about equal 

 to that produced by alcohol alone {table II, col. I). It is probable 

 that the alcohol, which is the better food, is largely responsible for this 

 growth, and that the acetate was left largely intact. If it had been 

 consumed in the usual way, the accumulation of acetic acid would 

 have stopped the growth of the cultures. The cultures containing 

 alcohol failed to fruit, while those containing only ethyl acetate fruited 

 abundantly. The spores from sets I and II, table X, were killed, as 

 no growth appeared when they were transferred to bean-stems. 



Acetic acid. — Acetic acid in its free state forms an efficient source 

 of carbon, but is so highly toxic that it must be used in extremely 

 dilute solutions. Nevertheless, two series of cultures placed the fact 

 of its assimilation beyond doubt. These are given here. 



TABLE XI 

 Acetic acid in each flask o.oi2g m ( = 0.004^). 



