420 CORRELATION OF PHYSICAL AND VITAL FORCES, 



H. RELATIONS OF LIGHT AND HEAT TO THE VITAL FORCES 

 OF ANIMALS. 



THOSE of our readers who accompanied us through the 

 first part of our inquiry are aware that it was our object to 

 show, that as force is never lost in the inorganic world, so 

 force is never created in the organic ; but that those various 

 operations of vegetable life which are sometimes vaguely 

 attributed to the agency of an occult " vital principle," and 

 are referred by more exact thinkers to certain Vital Forces 

 inherent in the organism of the plant, are really sustained by 

 solar light and heat. These, we have argued; supply to 

 each germ the whole power by which it builds itself up, at the 

 expense of the materials it draws from the Inorganic Uni- 

 verse, into the complete organism ; while the mode in which 

 that power is exerted (generally as vital force, specially as 

 the determining cause of the form peculiar to each type) de- 

 pends upon the "germinal capacity" or directive agency inher- 

 ent in each particular germ. The first stage in this construc- 

 tive operation consists in the production of certain organic 

 compounds of a purely chemical nature such as gum, starch, 

 sugar, chlorophyll, oil, and albumen at the expense of the 

 oxygen, hydrogen, carbon, and nitrogen derived from the 

 water, carbonic acid, and ammonia of the atmosphere ; 

 whilst the second consists in the further elevation of a portion 

 of these organic compounds to the rank of organized tissue 

 possessing attributes distinctively vital. Of the whole amount 

 of organic compounds generated by the plant, it is but a 

 comparatively small part (a) that undergoes this progressive 

 metamorphosis into living tissue. Another small proportion 

 (b) undergoes a retrograde metamorphosis, by which the orig- 

 inal binary components are reproduced ; and in this descent 

 of organic compounds to the lower plane, the power con- 



