1908] 



HASSELBRING— ASSIMILATION OF PENICILLIUM 



187 



TABLE XV 



In this series the amount of CH3COOK was 0.988™ per flask, but the magnesium 



content was varied. 



Number 



3 

 4 



5 



6 



7 

 S 



9- 

 II 



II 



i^"" MgSO* per 100" 



S 

 20 



37 

 39 

 41 



47 



55 

 64 



in 



rhe potassium acetate cultures show a remarkable uniformity 

 d, which is independent of the concentration of the acetate, exc 

 'cry dilute solutions and probably also in very concentrated sc 



tions. The lowest concentration in tables IX and X is too d 

 allow the full develoDment of the funerus under those conditions 



concentrations give the same 

 he increase of magnesium in t 



XV 



A higher concentration 



becomes poisonous 



In the growth of all the pot 



fungu; 



•nly 



radicle is taken 



KHCO 



precipitation of NH^MgPO^, thus keeping the culture neutral or only 

 slightly alkaline for a time. Wlien all the Mg is precipitated, the 



alkalinity prevents further grow 



The 



period, and hence gives a greater 



The yield is 



practically quantitative for a certain amount of ^Ig, and is independ 



amount of CH 



The potassium acetate cultures brought out the striking difference 

 ia power of resistance to deleterious substances possessed by different 



spores from the same culture 



ibserved in other cases 



deleterious concentrations of substances werc used, but it was 



potassium acetate cultui^ 



the 



method of inoculation, it is likely that more than a thousand spores 

 were sown in each flask. In the favorable media a large percentage 



