16 CHEMISTRY AND PHYSICS IN RELATION 



THE POWER OF THE SUN IN ATTRACTING WATER. 



The fact of the impracticability of working some mines in the height of 

 summer, owing to the veins or shafts being filled with water, has led naturalists 

 to ascribe to the beams of the sun a power of attracting water, which, according 

 to them is to be naturally explained by the action of the sun in drying up the soil, 

 whence hollow spaces are formed which are again filled from below by capillary 

 action. We know that a connection between the sun and the water takes place 

 within the mine, but this simply depends upon the drying up of the brooks in 

 summer ; as the pumps which are destined to draw away daily an equal quantity 

 of water, are impeded in their action by the stoppage of supply from these 

 sources. 



An analogous explanation may be given of the connection between the immo- 

 derate use of spirituous liquors and self-combustion, since it is most probable 

 that none but drunkards would be likely to fall into the fire, and be thus con- 

 sumed. 



THE IDEA OF BOERHAVE ON THE ORIGIN OF ALKALIS IN PLANTS. 



The false ideas concerning vital and material forces, which at this moment 

 separate by an unfathomable abyss, the department of physiology from that of 

 chemistry, arise entirely from the absence of true, and the presence of erroneous 

 views ; thus the ideas entertained in the eighteenth century of the occurrence 

 of alkalies in plants, may be placed side by side with those entertained in 

 pathology at the present day concerning the growth of a crystal, and the nutri- 

 tion of an organic being. According to Boerhave the alkali belonged neither to 

 the sap nor to the individual parts of the plant, but was a product of the pro- 

 cess of combustion ; and he represented to his hearers that decayed wood yielded 

 no alkali which was as little a constituent of the plant as the glass, which many 

 plants give on incineration. 



i 



FALSE COMPARISON BETWEEN THE COHESIVE FORCE OF CRYSTAL- 

 LIZATION AND THE ORGANIC FORCE. 



" Crystals like cells," so says Henle in his (Rationelle Pathologic,)* " are 

 restricted even under the most favorable conditions to a final limit of growth, 

 although the former are less narrowly circumscribed than the latter. Crystals 

 associate themselves together like cells in aggregate bodies, reminding us by their 

 arborescent arrangement of the elementary parts in the higher plants. Material 

 and vital bodies offer a certain measurable degree of resistance to external 

 influences, but accommodate themselves to circumstances, even changing their 

 forms occasionally. The most remarkable point of similarity between crystals 

 and organized beings, is shown after injury from external influences. Crystals 

 like organic bodies have the power of regenerating lost parts more or less fully. 

 In both, the force which formed the body continues at work, independently of the 

 matter which it has survived, or replaced. Thus if a crystal from which the 

 angles have been cut off be laid in a fluid whence it may draw a substance 

 analogous in composition to itself, it will increase generally, but more especially 

 in the direction of the part where it was injured, so that the regular figure is first 

 restored, just as an injured animal will, before all else, regenerate any lost part as 

 far as typical laws permit regeneration in his individual case." 



* Part i. p. 101. 



