MYCOLOGY DURING THE PAST FIFTY YEARS 573 



host to the positional location and to the host range of the Laboulbenialean 

 parasites upon them, as shown by Benjamin, while the diverse and effective 

 mechanisms of spore discharge in various fungi have been clarified by the 

 work of Ingold and others and the fascinating chronicle of the diversity and 

 efficiency of the adroit devices for the capture and utilization of amoebae, 

 rhizopods, rotifers, and nematodes by certain molds in the soil has been 

 recorded in detail by Drechsler. 



Toward better understanding of the mechanisms operative in the funda- 

 mental activities of organisms, the utilization of fungi as experimental ma- 

 terial has contributed significant and stimulating advances. In the category 

 of response to environmental conditions, the investigation of reaction to light 

 of different intensities and different wave lengths has found in fungi the 

 advantages of comparable development in darkness and in light, with also a 

 favorable lack of any of the complications involved in photosynthesis in green 

 plants. As an example, Phycomyces has become for such investigation the 

 classic material with which the work of Castle and others has yielded signifi- 

 cant evidence as to the location of the zones of sensitivity, the range and limits 

 of response, and the nature and extent of the resulting growth. Also in the 

 problems involved in survival and in continuation of activity under severe and 

 extreme conditions, the investigation of the molds concerned in the black 

 spotting of cold stored meats, or active in retting of guayule, or in the heating 

 of damp hay at thermophilic levels, or in the spoiling of canned fruits or 

 other foodstuffs preserved in concentrated media of high osmotic tension has 

 yielded results of considerable interest. In addition, the fungi have come to 

 play an increasingly important part in the experimental exploration of the 

 biochemical pathways of significant physiological mechanisms, cycles, and 

 processes. They have been found useful as specialized and effective agents for 

 the production of various essential enzymes, of important substances such as 

 riboflavin, of rare organic acids, and of unusual pigments. They have rendered 

 valuable services as prolific sources of vitamins of the Bio complex, as sensi- 

 tive instruments for bioassay and for the detection of minute quantities of 

 substances essential for growth. In all these capacities, the fungi have played 

 an important part in the advances which have been made. Furthermore, they 

 have rendered an important service as the agents for the exploration of the 

 mechanism of degradation of complex organic substances such as cellulose, 

 lignin, chitin, and keratin. The utilization of especially suitable and advan- 

 tageous fungi in these fundamental lines of investigation has resulted in a 

 notable extension of our knowledge of such features as the biochemical path- 

 ways by which degradation is accomplished, the sequence of the breakdown 

 products which result, and the vulnerability of the structural linkages in 

 these complex molecules. In contrast to the vulnerability of these natural 

 substances is the relative invulnerability to fungus attack of man-made 

 fibers of comparable complexity, such as nylon, dacron, and orlon. Consider- 



