204 



PART III. PHYSIOLOGY. 



[ 45 



as in the Aracese, where the inflorescence consists of a great num- 

 ber of flowers which open simultaneously, and which are protected 

 by a large leaf, the spathe, a rise of temperature as much as 18 O 

 has been observed. 



The few plants in which an evolution of energy in the form of 

 light has been clearly established are 

 all Fungi. It is commonly termed 

 phosphorescence. The so-called phos- 

 phorescence of decaying wood is due to 

 the presence of the mycelium of Agar- 

 icus melons, and that of putrefying 

 meat and vegetables to Schizornycetes 

 of the nature of Micrococci. Various 

 other species of Agaricus have been 

 found to be luminous. 



Movement of some kind is manifested 

 by all plants. All plants exhibit that 

 slow movement which is termed 

 growth : in many, there is a more or 

 less well-marked movement of the pro- 

 toplasm in the cell or cells of which the 

 plant-body consists, which is known as 

 cydosis, circulation, or rotation :. some 

 are capable of locomotion during the 

 whole or a portion of their life, a 

 peculiarity which is shared by many 

 reproductive cells, such, as zoospores 

 and spermatozoids : in some cases, the 

 floral or the foliage-leaves of the plant 

 can perform movements, as the foliage- 

 leaves of the Sensitive Plant, of the 

 Telegraph-plant, of Dioncea muscipiila 

 (Venus' Fly-trap), the stamens of Ber- 

 beris and of the Cynareae, or portions 

 of leaves as the tentacles of Drosera 

 (Sun-dew, see p. 189). These movements 

 are considered in detail in the next 

 chapter. 



The connexion between these various 

 forms of dissipation of energy and the 

 catabolic processes, is clearly demon- 



Fio. 129. Apparatus for de- 

 tecting the rise of temperature 

 in 8mp.ll opening flowers or ger- 

 minating seeds. The seeds are 

 heaped as closely as possible in 

 the funnel r which is inserted 

 into the mouth of a bottle con- 

 taining a solution of caustic 

 potash. This absorbs the car- 

 bon dioxide produced by respi- 

 ration. The whole is enclosed 

 in a glass vessel, and a delicate 

 therm oraeter is inserted through 

 the cotton wool which closes 

 the mouth. The bulb of the 

 thermometer is plunged in 

 among the seeds. The tempera- 

 ture in this apparatus will be 

 higher than in another arranged 

 in the same way forcompnrison, 

 and in which the flowers or 

 seeds have previously been 

 Ic.lled. 



