CHATTER XLTT. 



STIML LATIN K l.\ Fl.UEM KS — CHNHJiAL IJEMAKKS uN 

 THE ENZYMES UF EUMYCETES. 



;j 232. -Influence of Light on the Development of the 



Eumycetes. 



According to an old oolloquial expression, the fnngi are children 

 of darkness. This statement, however, is only api)ropriate in 

 certain instances, more particularly in the subterranean species, 

 e.ij. the trullle, and is by no means capable of general applica- 

 tion. The first to protest against this generali.sjition was 

 E. M. Fries who slioweil, in 1825, that light is indispeiisjible to 

 the normal devek))tment of certain fungi. Following his lead, 

 a large number of workers have since inve.stigated the con- 

 nection between light and fungoid life ; but oidy a few of the 

 re.sults obtained can now be brietly recapitidated, namelv, tho.se 

 concerned witli the fungi of intere.st to readers of the pre.sent 

 work. We will al.so le«\ve out of consideration the older reports 

 dealing with the malformed growths — due to defective illumina- 

 tion- of fungi in mines, where they dnig out a mi.><enible 

 existence; and also the (barren) mycelial mas.ses found in mine 

 shafts and headings, and de.scribed, in the older literature, under 

 tin' collective name of lii/ss-im. Information on this question 

 will l»e found in a woik by Elfvixg (I.), to which we shall have 

 occasion to refer later on. 



The fii'st phenomenon we shall Jiow consider is one that will 

 bt»coim> ajiparent on even merely superticial observation, namely 

 phototropism. or the influence exerted by light on the direction 

 of growth. At the outset research was conflned to the narrower 

 tield of the form of ilhnnination mo>t common under natunil 

 conditions, viz. by the sun's rays (heliotropism) : and, according 

 as this influence proved .stimulative, rctiirdative, or inert^ the 

 fungi alYectt'd thereby were classed as jmsitively heliotropic, 

 negatively heliotro])ic, or aheliotropic. An example of each 

 of the two lattt'r possibilities was furnished by ,1. SriiMiTZ (I.) 

 in iS|; and l>y KiiAls (I.) in 1876, the latter of whom founcl 

 Ji/ii:.o)itis ///;/r/i(j//.-' {Mit'-iir fttn/oni/t'r) presumably aheliotropic. 

 Sehmitz observed that the mycelial threads at that time chi^sed 



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