EXPERIMENTS ON THE HEAT OF LIVING PLANTS. 



7 



the temperature of the air. Immediately after this phenomenon, moul- 

 diness is visible ; the farinaceous grains become acid by fermentation, 

 and then all power of germination is at an end. The seeds which 

 contain azote, such as kidney beans, requiring four or five days to 

 germinate, are not proper for experiments; because, after so long a 

 space of time, a part has already become putrid. The same observation 

 may be made of mucilaginous grains : consequently, the grains that may 

 be employed with most success are those which germinate very quickly. 

 To prevent a premature budding of the mouldiness, care should be taken 

 to choose a time when the temperature is not very high. The heat of 

 grains when germinating rises rapidly, and stops at a moderate height : 

 it usually rises some degrees higher, when decay, or acidity from fer- 

 mentation, appears. The first representation that the author gives of 

 these experiments indicates the development of heat in wheat, oats, 

 and maize, during thirteen days successively. At a moderate tempe- 

 rature of 11-12°, wheat arose after the third day to 20° ; at which it 

 remained during three days. Then appeared symptoms of decay and 

 acidity, which successively caused the thermometer to rise to 28°. The 

 oats exhibited nearly the same results. The maize rose about the time 

 indicating 16°. On the thirteenth day only signs of decomposition 

 appeared. The results obtained from peas and hemp differed but little 

 from those produced by monocotyledonous plants. The grains hitherto 

 submitted to experiments possessing a great deal of fecula, the author 

 sought to discover the phenomena presented by the germination of those 

 plants which do not possess any ; for this purpose he made experiments 

 on the following plants: Triqfolium repens, Brassica napus, Spergula 

 arvensis, and Carum Carui ; they produced the same results ; and 

 therefore prove that the quantity of fermenting substances has no in- 

 fluence whatever on the quantity of caloric disengaged, and that we 

 cannot explain the development of heat by a simple process. Experi- 

 ments made on considerable quantities of wheat leave not the least 

 doubt that the sugar developed during germination may be only the 

 result of an organic operation, and that the caloric disengaged owes its 

 existence to the vital power of the vegetable only, and not to a 

 process of combustion, an opinion adopted in preference by chemists to 

 explain the increase of the temperature. 



B. Experiments made with bulbs and tubercles. — Those which 

 were made on potatoes, radishes, and other large tubercles, produced 

 no results ; it being impossible to make observations on them. The 

 author consequently proceeded by the method employed with seeds. 



