ALTERATIONS WHICH THE NUTRIMENT UNDERGOES. 557 



after 48 hours (where there is no interference with 

 growth) a colony consisting of two hundred and fifty- 

 six billions of individuals ; and this colony will, accord- 

 ing to Nageli's estimation, represent a weight when Estimation of 

 dry of about eight grammes, which consist chiefly of 

 albuminoid substances. During the next hour sixteen required, 

 grammes, and after a second hour thirty-two grammes 

 of the nutrient solution will be transformed into 

 fungus tissue ; and in the course of the third day, 

 more especially where we commence with a number 

 instead of a single individual, we have truly colossal 

 numbers which as a matter of fact are only not 

 usually met with, because the close aggregation of the 

 fungi and the production of noxious materials as the 

 result of their growth hinders their free development. 



Finally, as regards the interchange of energy, which interchange 

 accompanies the tissue change of the fungi, we do not as 

 yet know anything directly, but can only draw conclusions fungi, 

 from analogies with the higher plants. As regards the 

 amount of energy taken in, the state of matters in the 

 lower fungi differs somewhat in that it is practically 

 only the chemical transformations of which we spoke 

 above which furnish the necessary energy. In the case 

 of the higher plants the rays of light supply the energy 

 necessary for the assimilation of carbon ; but the fungi 

 which do not contain chlorophyll are unable to utilise 

 this source of energy, and the whole assimilatory process 

 takes place at the expense of the energy which has been 

 liberated by chemical decomposition. 



The energy which has been obtained by the respiratory 

 process is used up partly in the process of assimilation 

 and partly in the further combinations of the materials ; 

 also in the process of growth and germination ; in loco- 

 motion ; and finally in the production of heat and light. 

 As regards the consumption of energy in the processes 

 first referred to, we have no precise knowledge. In the 

 process of growth, more especially in the case of the 

 fission fungi, a large quantity of energy is often used up; 

 rapid growth will therefore always go hand in hand with 

 free respiration and the production of carbonic acid. A 



