244 VIEWS, &C. PHYSIOGNOMY OF PLANTS. 



brought to Europe." This enfeeblement of the vital functions 

 and vital activity passes through several gradations, accord- 

 ing as it extends to the processes of nutrition, respiration and 

 muscular movement, or induces a depression of the cerebral 

 and nervous systems. The winter-sleep of the solitary bear 

 and of the badger is not attended with rigidity, and hence 

 the awakening of these animals is easy, and, as I frequently 

 heard in Siberia, very dangerous to the hunters and country 

 people. The recognition of the gradation and connec- 

 tion of these phenomena leads us to the so-called vita minima, 

 of the microscopic organisms, which occasionally fall in the 

 Atlantic in showers of meteoric dust, and some of which have 

 green ovaries and are engaged in a self-generating process. 

 The apparent revivification of the Rotifera and of the sili- 

 ceous-shelled Infusoria is only the renewal of long enfeebled 

 vital functions — a condition of vitality never entirely extin- 

 guished, but merely revived by excitation. Physiological 

 phenomena can only be comprehended by being traced 

 through the entire series of analogous modifications. 



(4) p. 211—" Winged Insects." 



The fructification of dioecious plants was at one time princi- 

 pally ascribed to the agency of the wind. It has been shown 

 by Kolreuter, and also with much ingenuity by Sprengel, that 

 bees, wasps and numerous small winged insects, are the main 

 agents in this process. I use the phrase "main agents", since 

 I cannot regard it as consonant to nature that fructification 

 should be impossible without the intervention of these insects, 

 as Willdenow has also fully shewn. * On the other hand 

 dichogamy, sap-marks, {macula; i?idicantes), coloured spots 

 indicating the presence of honey-vessels, and fructification by 

 insects, appear to be almost inseparable from one another.f 



The statement often repeated since Spallanzani, that the 

 dioecious common hemp (Cannabis sativa), which was intro- 

 duced into Europe from Persia, bears ripe seeds without being- 

 in the neighbourhood of pollen-tubes, has been entirely 

 refuted by more recent investigations. When seeds have 

 been obtained, anthers in a rudimentary state have been found 

 near the ovarium, and these may have been capable of yield- 



* Grundriss der Krauterkunde, 4te Aufl. Berl. 1805. s. 405 — 412. 

 ■f Auguste de St. Hilaire, Lemons de Botanique, 1840, pp. 565— 571. 



