1 6 RE PR OD UCTION 



of compounds. These may be briefly summarized under the fol- 

 lowing groups : 



1. Hydrocarbons, including sugar of the glucose type, glycogen, 

 gums (notably hchenin), mannite, and a number of other forms. 



2. Organic acids, among which are oxalic, malic, citric and lac- 

 tic acid. 



3. Aromatic acids. Nineteen forms are described by Zopf.* 



4. Fats. 



5. Ethereal oils. 



6. Resins. 



7. Coloring matters in great variety. Over thirty forms are 

 described by Zopf.f These include various shades of brown, 

 blues, purples, yellows, reds and greens, 



8. Alkaloids, among which muscarin and ergotinare among the 

 best known. The former is found abundant in the fly-agaric, 

 and is probably a common cause of mushroom poisoning. The 

 latter forms the basis of the ergot poisoning in animals, and is 

 one of the deadly drugs of the pharmacists. Zopf t enumerates 

 twelve different alkaloids found in fungi. 



9. Cholesterin. 



10. Albuminoids of various forms. 



Besides the ordinary elements of organic food, carbon, hydrogen, 

 oxygen and nitrogen, fungi require sulphur, phosphorus, one of 

 the alkali metals (commonly potassium), and one of the alkali 

 earth metals (more commonly calcium). These food stuffs are 

 obtained (i) From decaying organic substances, or (2) From the 

 living cells of other plants or animals. Fungi which obtain their 

 nourishment by the former method are called saprophytic. Those 

 preying on other organisms are called parasitic. A plant or ani- 

 mals which supports a parasite is commonly called its host. 



Fungi require for profuse growth considerable moisture and a 

 moderate degree of warmth. The optimum temperature for the 

 growth of the conidia of the common green mould {Penicillium 

 crustaceimi) according to Wiesner is 22° C, the minimum being 

 i.5°-2° C, and the maximum being 4o°-43° C. Other fungi 

 vary a few degrees from these figures. While certain fleshy fungi 



*Die Pilze, 131-138. Schenk, Handbuch der Botanik, 4 : 401-408. 

 '\ Loc. cit., 143-163. (Schenk, loc. cit.^ 413-433). 

 XLoc. cit., 163-166. (Schenk, loc. cit., 433-436.) 



