INl'LUKXCE OK LKiHT ON EUMYc KTES. 55 



of Phycornijces nitt^ii^. Tlie existence of after elTet-ts of htiniula- 

 tion WHS first reimirketl, in this comiection, by Wiekxeb (I.). 



Although the iiillueHfe of light on all the other vit:il 

 manifestations of fungi has been the subject of numerous 

 observations and experiments, no unifornt results have been 

 secured, nor has the stime elevate<l point of view been attained 

 as is the case— thanks to Oltmanns — with regard to its influ- 

 ence on the direction of growth. In dealing with tins next 

 question, we will follow the natural course of development, and 

 liegiii with the influence of light on the germination of the 

 spore. Now, acconling to 11. Hkk.maNN (11.), or ratla-r K. Lokw 

 (III.), germination is not affected in the case of the conidia 

 of PenicUliitm <jlaiicuin, Tricutherium rosriim, and J-'u-^arium 

 lieti'r(>xi>oriuiii, or the endospores of Rhizcjms ni-jrirauK {Muror 

 sti)tiini/er). Contrary results were afterwards ol)tiiined by vox 

 Weitsteix (I.), who found germination retarded by light in the 

 case of spores of RhMlomycex KorJiii ; and by F. Klkvixg (I.), 

 who proved that intense sunlight entirely prevents germination 

 in the conidia of Asi/rriji/hts i//aitruis. 



The reports of experimentei's al.so differ with regard to the 

 influence of light on the vegetative development — increase in 

 the size oi tiie clIIs, and the power of growth. Thus, wherea.*!, 

 according to a report by J. Schmitz (I.), SjiJu'rid ctiijiuphila 

 grows more strongly in the dark than in daylight, I^eziza 

 Furkeliaiin — according to (5. Wixtek (I.) — ceases to grow in the 

 dark, and perishes entirely if the exclusion of light be prolonged. 

 Vax Tieghem (IX.) and Oaillaud (I.) found illumination exercise 

 a favourable influence on the development of Ptnifiltiuiu and 

 certain yeasts respectively. KuAl's (I.), on the other han<l, 

 found the perithecial liypha^ of C/arii;j)i< }nirrw> fihahi attiiin 

 their greatest length in the dark, rather than in red, yellow, or 

 blue light. Brefeld al.so made the sjime observation with regard 

 to the stalks of cert;iin species of Ci>j,riiiuf. (\. H. VlXES (I.) 

 found the growth of the sporangial hyplue of I'liijcoinijo-^s niteriK 

 prejudicially affected by light, and traced this action to the 

 influence of the blue rays. 



Tiie first to investigate the influence of light on cell fission, 

 and therefore on cell reproduction, w.is L. Knv (1.), in the case 

 of i)re.ssed veast. He failed to di.scover anv ditVerence in the 

 rate of reproduction in the ilark and under minlerate illumina- 

 tion by gaslight. This is, however, altered in tlu> ca.se of strong 

 insolation, as will be referreil to later on. 



Al.so in respect of fructification the individual speiies of 

 fungi seem to dilVer with regard to the strength of illumination 

 neces.sjvry to the production of a given result ; such at least is 

 the conclusion furnished by compiring the reports of variouu 

 observations conducted on this point, the original probability, 

 based on considerations of a general physiological character, 



