ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 633 



that it seldom remains quite constant even when the state of the 

 plants submitted to it remains imchanged. Practical scientific 

 results can only be obtained by the use of the calorimeter, which has 

 been applied by G. Bonnier in the following manner : — 



Seeds which are either germinating or about to germinate are 

 placed in the water of Berthelot's calorimeter, and the temperature 

 of the water observed every minute ; if it is necessary that the 

 germination should be undergone in the air, the proper amount of 

 seed is enclosed in a blackened platinum vessel which is placed in 

 the calorimeter. The number of heat-units developed or absorbed is 

 determined by the temperature of the thermometer taken in con- 

 nection with the specific heat and the weight of the materials used. 

 Among other precautions in reading the results, allowance must be 

 made on the one hand for the action of exosmose in extracting 

 substances from the seeds and the consequent loss of heat by their 

 absorption in the water, and on the other for the production of heat 

 by the development of organic ferments which have nothing to do 

 with the germination. By this method Bonnier has determined the 

 amounts of heat evolved in various stages of the germination of 

 castor-oil, pea, bean, rye, and lupin seeds, identical weights of each 

 being used for identical periods during the different stages. Thus 

 the quantity of heat developed between the commencement of the 

 process and the formation of chlorophyll is determined, and amounts 

 to 1° and upwards per minute. The number of calories (units 

 which are equivalent to the raising of 1 kilogramme of water thi-ough 

 1° C.) varies up to 120 in this experiment, shows an increase in all 

 the species of seeds, and passes through a maximum period. The 

 total amount of heat developed during the germination of the pea has 

 been determined ; it does not represent, as one would have expected, 

 the amount necessary to produce the carbonic acid which is formed at 

 this time. 



Inulin.* — Having closely investigated the chemical composition 

 and physical properties of inulin, H. Kiliani gives the following 

 epitome of results. 



The horn-like inulin is distinguished from the so-called crystalline 

 modification by containing more water. The specific gravity, when 

 deprived of water, is 1 ■ 3491. The specific power of rotation of dahlia- 

 inulin, free of water, and dissolved in hot water, is — 36° 54' at 20°-23° 

 C. ; when dissolved in cold potassa it is — 34° • 6 at 20° C. Air-dried 

 inulin has no definite composition. That from the dahlia or from 

 Inula dried at 100° has the composition G2qB.q2^2i ; no more water is 

 lost by heating to 130°. Inulin always contains traces of incombus- 

 tible substances, viz. calcium phosphate and some nitrogenous sub- 

 stance. It melts between 160° and 170° C. Invertin does not con- 

 vert it into levulose. It does not reduce Fehling's solution. From 

 an ammoniacal silver-solution or gold chloride it separates the metal 

 on heating. Platinum chloride and mercury chloride are not changed. 



* Kiliani, H., ' Ueber Inulin : Inaug.-Diss., gekronte Preisschr.' Miinchen, 

 1880. See Bot. Centralbl., ii. (1880) p. 656. 



