K.— BOTANY 199 



between the fungus and root is not of the same general type as in orchids. 

 Trees growing under certain conditions undoubtedly benefit from the 

 presence of the fungus, and forestry research-workers are investigating the 

 problem of artificially infecting seedlings with appropriate fungi. Food 

 obviously passes from the mycorrhizal fungi into the tree roots whether the 

 food is absorbed from the fungus itself or is formed in the soil by the 

 action of the fungus on substances present there. 



Fungi are able to bring about changes by means of enzymes, and it is 

 surprising what veritable museums of enzymes many fungi are, e.g. from 

 Aspergillus Oryzee the following have been recorded : amidase, catalase, 

 cytase, dextrase, diastase, emulsin, a and (3 glucosidase, glycero- 

 phosphatase, histozyme, inulase, invertase, lactase, lecithinase, lipase, 

 maltase, protease, rennet, sulphatase — apparently sufficient for any purpose 

 here below 



It is puzzling why with such a battery of attack many fungi are not 

 more nearly omnivorous ; obviously other factors in addition to enzyme 

 action enter into the problem. One thing is sure — there are abundant 

 species and there is abundant decay. But all decay is not destruction, 

 and life — so long as it remained possible — would be odd without the 

 changes brought about by fungi. 



From earliest times man has made use of the action of certain fungi 

 for bringing about desired changes in food and drink. More recently 

 many of these processes have been carried out under controlled conditions, 

 and other fermentations -have been harnessed by man for his need, his 

 pleasure, or his convenience. Fungi are rapidly becoming more important 

 in this respect, and we may anticipate an increasing number of industrial 

 applications of fermentation activities. There is every sign that eventually 

 we shall have a great chemical fermentation industry producing many 

 substances which are now manufactured by expensive synthetic methods, 

 for many such substances are known to occur as metabolic products of 

 micro-organisms. Regarding the formation of these products, A. J. 

 Kluyver writes : ' Even a superficial survey of the biochemical field is apt 

 to fill one with profound astonishment at the practically unlimited diversity 

 of the chemical constituents of living organisms. But this astonishment 

 is transformed into bewilderment when we take into consideration the 

 chemical processes which lead to the formation of these various products. 

 For we have to accept the undeniable fact that all these substances have 

 ultimately been derived from carbon dioxide and inorganic salts by a more 

 or less elaborate series of biochemical processes. . . . Here we find the 

 most remarkable fact . . . that a single organic compound suffices to 

 ensure a perfectly normal development of these organisms, although they 

 are cut off from any external energy supply. Here we find the biochemical 

 miracle in its fullest sense, for we are bound to conclude that all the widely 

 divergent chemical constituents of the cell have been built up from the 

 only organic food constituent, and that without any intervention of 

 external energy sources. The chemical conversions performed by these 

 organisms rather resemble witchcraft than chemistry ! ' The Great War 

 stimulated much research in these problems, and some of the methods 

 then devised have been improved and extended just as Pasteur's studies 



