104 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Alter noticing the various arguments and illustrations which have 

 been adduced in its support, he discusses the results wliich have heon 

 obtained iVom experiments in lichen-culture, whether from the sjjore or 

 by synthesis, which he considers were confessedly but small, owing to 

 the very great difficulty of cultivation beyond a rudimentary stage. 

 There are in the author's oi)inion two fatal objections to the theory : 

 the one having reference to the very peculiar nature of the parasitism 

 assumed, and the other to the fact that, notwithstanding a similarity of 

 appearance, there are in reality no true fungal mycolia nor true algal 

 colonies in lichens. As to any direct genetic or any indirect parasi- 

 tical connection between the gonidia of lichens and the hyphal fila- 

 ment, they do not exist ; but on tracing the evolution of the thallus 

 from the germinating spore, it is seen that the gonidia originate in the 

 cellules of the tirst parenchymatous tissue formed upon the hypo- 

 thallus, and that subsequently, through the resori)tiou of the lower 

 portion of the cortical stratum, they become free, and constitute the 

 thin gonidial stratum. Where seen lying amongst the medullary 

 hypha) they ai*e often attached to these, not as the result of any copu- 

 lation, but by means of the licheuin which permeates the whole 

 thallus. " Schw'endenerism, whether viewed anatomically or bio- 

 logically, analytically or synthetically, is, instead of being true 

 science, only the ' Romance of Lichenology ' ; and thus also the 

 origin of the gonidia in, and their relation to, the rest of the lichen- 

 thallus belong to the very rudiments of morphological botany, and 

 constitute the A B C of Lichenology." 



Fungi. 



Respiration and Transpiration of Fungi.*— G. Bonnier and L. 

 Mangin describe in detail a series of experiments on this subject, as 

 well as the apparatus used, from which the following general results 

 were obtained : — 



Respiration is augmented by a rise of temperature ; there is no 

 optimum <^)f temperature for respiration. Diffused light, on the other 

 hand, retards respiration. The more refrangible rays of light are, as 

 a whole, more favourable to respiration than the less refrangible. 

 Respiration increases with the hygrometric state of the air. The 



C 



value of the fraction '^ , i. e. the proportion of carbonic acid 



evolved to that of oxygen absorbed, varies with different species ; it is 



in general less than unity. Assimilation of oxygen does occur in fungi. 



C O 

 For the same species the value of — -^ does not vary with the pressure, 



nor with the temperature. 



Transpiration increases with a rise of temperature, and diminishes 

 as the hygrometric state of the air increases. Diffused light i^ro- 

 motes transpiration in fungi. 



* Ann. Sci. Nat., xvii. (1884) pp. 210-305, Sue supra, p. 'J7 ; also tliis 

 Journal, iii. (1883) p. 3'JtJ. 



