(33 



wheat-grains, on which I now wisli to make a short preliminair}' 

 communication. 



The germination of the wheat-grains nnder observation always 

 took pUice at about 20^ C in the dark, Ihere could therefore be no 

 energy taken up from williout by assimilation oi' carbon dioxide ; 

 all the energy needed for the processes of germination had therefore 

 to be [n'ovided by moans of the reserve materials. 



At the commencement of germination ind)ibition chielly takes 

 place, in this way heat is already liberated, therefore energy ; then 

 there follow very soon a series of exothermic pi-ocesses, in wdieat- 

 grains more especially decom})osition of starch to sugars and com- 

 plete oxydation of this material of respiration to carl)on dioxide. 

 The energy set free in this manner is now applied to varions ends : 

 1st. fQi- j^ii kinds of synthetic processes by means of which plastic 

 materials are formed for the growing plant, 2"'^. for the production 

 of osmotic pressure, 3"^ for the overcoming of internal and external 

 resistances, and 4'''. energy is given otf in the form of heat-radiation. 



The methods used to obtain an insight into these various energy- 

 relations were the two following : 



1^'. Determination of the heat of cond)ustion before germination, 

 and after the gernunation had been progressing for some time. 



2"'^. Determination of the quantity of heat produced during ger- 

 mination. 



As regards the first point, it must be pointed out that the internal 

 chemical energy during a certain length of germination must decrease; 

 a measure of this loss can be found by determining the difference 

 in the heat of combustion. The energy which will no longer be 

 shown by this heat of combustion, is that which is utilized osmoti- 

 cally, for overcoming resistances and which is lost by the giving out 

 of heat. The energy, however, w liicli is nsed up during germination 

 for synthetic processes is again tixed as chemical energy and is 

 indeed represented by the heat of combustion. 



The loss of energy, that is found by determinations of the heat of 

 'combustion, does not give therefore the total amount of energy, 

 which has played a part during gei-mination, for a considerable part 

 of this energy has again been withdrawn from observation by the 

 synthetic processes. 



The BERTHELOT-bomb was used for determining the heat of com- 

 bustion. In it a weighed quantity of wheat-grain's, germiiuited or 

 ungermiuated and previously dried for a long time at 100°. were 

 buiHit ; by the rise of temperature of the water in which the l)0inl 



