354 DIVISION III.—MODE OF LIFE OF THE FUNGI. 
they can only take up their food in a fluid or gaseous condition. The general 
difference between the process of nutrition in the Fungi and in plants which contain 
chlorophyll and similar substances consists in their inability from want of chloro- 
phyll to decompose carbon dioxide. They must obtain their carbon by taking 
up organic carbon-compounds previously formed in some other bodies, as is the 
case with all organisms or parts of organisms which do not contain chlorophyll. 
According to experiments with Moulds and Saccharomycetes in artificial nutrient 
solutions, the nitrogen is taken up and disposed of to the benefit of the plant in the 
form of inorganic compounds, provided the carbon is obtained as some organic 
compound such as sugar ; Moulds like Penicillium, Mucor racemosus, and Aspergillus 
niger (Pasteur, Fitz, Raulin) take up nitrogen from ammonia-compounds as well as 
from nitrates, while ammonia is a good and nitric-acid a very indifferent source of 
nitrogen ‘for the Veast-saccharomycetes (Mayer, Nägeli)’. Moreover the need 
of carbon as well as that of nitrogen may be supplied in the same Fungi by means of 
organic compounds which they are able to take up; some of these supply more 
nutrition than others, and some supply none at all. According to Nageli almost all 
compounds of carbon afford nourishment with the addition of oxygen, provided they 
are soluble in water and not too poisonous. Urea, formic acid, oxalic acid and oxamide 
(Nageli) besides CO, and cyanogen are exceptions to this rule. A large number 
of compounds may serve as sources of nitrogen, if they are in a soluble state or can 
be made soluble by the Fungus. Free nitrogen and cyanogen cannot by themselves 
supply nourishment. Some compounds containing nitrogen may serve at the same 
time as sources of nitrogen and of carbon, others, as oxamide and urea, only as 
sources of nitrogen. According to Nägeli, Penicillium grows best in a solution of 
proteid (peptone) and sugar ; then in the following solutions arranged in descendihg 
order according to their nutritive capabilities: 1. leucine and sugar; 2. ammonium 
tartrate or sal-ammoniac and sugar; 3. proteid (peptone); 4. leucine; 5. ammonium 
tartrate, ammonium succinate, asparagin; 6. ammonium acetate. 
As regards the constituents of the ash the requirements of the Fungi are 
essentially the same as those of other plants, but with this limitation according 
to Nägeli ?, that Fungi are comparatively less particular in their selection. 
“Fhe amount of available food-material in the substratum is not the only point of 
importance; its chemical nature also has to be considered, as was intimated 
above in the account of the conditions required for germination. Dutrochet ® 
discovered some time since that the development of Moulds was affected by the acid 
or alkaline reaction of the fluids in which they grew, and more recent investiga- 
tions, dating from the year 1860, have shown the existence of important specific 
differences in this respect in the Fungi. The common Moulds flourish in nutrient 
solutions which are more or less acid; they do not grow so well or refuse to grow 
in neutral or slightly alkaline fluids. ‘The Schizomycetes behave as a rule in the 
reverse way (vid. infra, Chap. XI). A trace of acid is sufficient to retard the develop- 

1 A review of the subject and its literature will be found in Pfeffer, Physiol. I, 242. See also 
Nägeli, Ernährung d. niederen Pilze (Untersuch. &c. 1882, 1, and Sitzgsber. d. Münchener Acad. 
Juli, 1879), and Raulin in Ann. d. sc. nat. ser. 5, XI (1869), 220. 
® Untersuchungen, 1882. ® Ann. d. sc. nat. ser. 2, I, p. 30. 
