INTRODUCTION TO CRYPTOGAMIC BOTANY. 265 



which were cooked in the evening were in some cases the 

 next morning covered with this production. The only instance 

 of similarly rapid development is that of yeast globules, 

 and it is there probably that we must look for the true solu- 

 tion of the question as to its real nature. Unfortunately, ex- 

 periments on the evolution of Fungi from single spores, require 

 nice manipulation and complete leisure. A few hours' avoca- 

 tion is sometimes fatal to such observations. 



263. It has been asserted that powerful odours are inimical 

 to the propagation of Fungi, and the freedom of Russian 

 leather from parasitic moulds has been quoted as a confirmation 

 of the notion. I fear, however, that it is not well founded, 

 except where the odour may be acccompanied by gaseous 

 matter inimical to vegetation ; and as regards Russian leather, 

 I can myself answer from my own experience that it is no 

 complete preservative in a damp atmosphere. 



264. One great peculiarity of Fungi is, that their relations 

 to the atmosphere are entirely different from Phaenogams. 

 They do not help to keep up the balance between animal and 

 vegetable life, so far as the atmosphere is concerned ; for, like 

 animals, they exhale carbonic acid and absorb oxygen, and it 

 is to this cause, probably, that the absence of vegetable green 

 in their cells is due. In some cases they are capable of gene- 

 rating considerable proper heat. Dutrochet found that the 

 highest temperature generated by any vegetable, with the 

 exception of Arum, was by Boletus ceneus. 



265. Some Fungi are remarkable for their luminous ap- 

 pearance at night, which is often so intense as to yield light 

 enough to read by. This luminosity has been observed 

 in various parts of the world ; and where the species has been 

 fully developed, it has been generally a species of Agaricus 

 which has yielded the phenomena. Agaricus olearius of the 

 south of Europe is one of the best known, but other species 

 have been observed, as Ag. Gardneri, Berk., in Brazil ; Ag. 

 lampas, and some others, in Australia ; in Amboyna, by Rumpf, 

 &c. Mr. Babington has observed imperfect mycelia extremely 

 luminous near Cambridge ; and Dr. Hooker speaks of the phe- 

 nomenon as common in Sikkim, though he was never able to 



