11 



turu li:i;l iigaiii risen, tlioiigli imt (juiti.' su \i\'j}\ :is atS a. in. After tlic lii'ups liavc 

 t)L'en lirokcn down b-jtween 1 p. m. ami 2 p. ni. tli'j vice continues to cool ; on tlie 

 öth tlic temperatni-c at 2 p. ni was 91'^9 and at 8 p.m. liad fallen to 88.8= F. 

 Tlio object, therefore, of the working of the mafS is not fo mueli to pre\ent 

 the grains becoming too innch matted together as to rcgnlatc the aclivily of the 

 growtli of the plant. If the grains were allowed to remain heaped np dnririg the 

 whole time, there would be a danger of the temperature rising to too high a 

 ]iiiiiit, and perha] s reiideiiiig the product useleps, whilst if the grains were never 

 collected into lieaps, the temperature wnuld ncit rise sufficiently high to allow tlie 

 growth to go on vigorously. 



The amoiint of heat generated during the giowlli of the I'lmgus is remarka- 

 ble, and will be best appreciated from the observations made in December. At 

 that time the temjiorafm-e of the open air in tin' sliade varied between 38° and 

 51= F, whilst in the subterranean chamber the temperature of the air was very 

 nearly constant and very much higher than that of the open air. The growing 

 chamber is not artificially heated except at slarl'i'g — that is, after having been 

 disused for a considerable time. It is then heated by the introduction of barrels 

 containing hot water, but after that, all the heat it receives is deri\-cd from the 

 growing plant. In December tl.v dilTerence between the outer and inner tem- 

 peratures amor.nts to as iniicli as 4 \- or 4.")= F, but in Sbsy the diiference is not 

 more than 10 or 12-' F. Kot onl\ is the heat generated during tlie growth of 

 the plant sufficient to keep the ch:imber hot, but it also raises the temperature of 

 the rice on tlie trays about 23'-' F above the m,a>;inii;in temperature of the cham- 

 ber. All this heat must be derived fiom the combustion of the rice, anil the 

 liljcratinn of its carbon and liydrogen in the form of carbonic acid and water. 

 'I'liat carbonic acid is fornud in large quantity is sb.own by tlie rapid removal of 

 tlie oxygen from a confined [oition of air by the actively gmwing jilant. A 

 handful of the mixture (n\ the trays was pr.t into a 1 ottle holding abcait 3 litres 

 of air, and the buttle was then tightly closed with a cork through which tubes 

 ]iasscd by means of whicli a sample of tlu^ air in the bottle could lie forced out 

 and ciillected fur analysis. During the time the bottle remained in thecliandier 

 the ends of these tubes were closed with caoutcliouc tubes and pinch-cocks. The 

 bottle was allowed to remain at the temperature of the chamber for four hom-s, 

 at tlic end of whiih time it was found that the whole of the oxygen in the three 

 litres of air h.ad iieen replaced by carbonie aeid. The grains of rice in the bottle 

 remained loose, wliilst those on the trays exjiosed to the free air of the chamber 

 were matted together. l'"riim this it may be inferred that the quanlily of oxygen 

 cotitiiined in the, bottle was insufKcient to generate the heat n'lir.ired by tlu^ 

 fungus fir its growth, which, theicroie, ceased as r(;on iis all the oxygen wjis 

 oohsiimed. 



The uxidalioh w liich goes on (b:i ing the growth of the fungus, and by wiii(.li 

 the heat is generated, is ed'eelcd mainly at tlie exixMise of the stardi contained in 

 flio a'l!« of till' L'l'.iin I la!r I repri seiils a section of a eiaiii of köji eut per- 



