THE METABOLISM OF PLANTS. 



2I 9 



resulting mycelium, instead of containing an abundance of 

 protoplasm, contains but little, and in this a number of oil- 

 drops are distributed (Fig. 30). It is obvious that, under 



Fig. 30 (after Cunningham). Hyphse of Choanephora, the upper one 

 well-nourished, the lower one starved. 



the conditions of the experiment, this oil could not have 

 been formed from any food materials absorbed from without, 

 and, when we note the diminished protoplasmic contents, 

 we cannot but correlate the diminution with the abundance 

 of oil, and conclude that the oil must have been formed 

 at their expense. Similar observations on Fungi have been 

 made by Naegeli. He finds that the nature of the food 

 supplied has but little influence upon the amount of fat 

 formed, and he inclines to the view that fat is formed from 

 the protoplasmic cell-contents. 



The experiments of Loew given in Naegeli's paper tend to prove the 

 formation of fat from the protoplasmic cell-contents. . Some Penicillium- 

 mycelium was left for four weeks in a dilute (i per cent.) solution of 

 phosphoric acid : analyses before and after gave the following results : 



the mycelium contained 



Proteid 

 Fat 



Cellulose j 

 Extractives)- 

 Ash ) 



before 

 427 



18-5 

 38-8 



after the experiment 



16*5 per cent. 



Admitting that the fats are formed from the protoplasmic 

 cell-contents, we have yet to ascertain whether they are 

 derived from the living protoplasm or organised proteid, or 

 from the dead unorganised proteid. If, as suggested in pre- 



