INORGANIC SUBSTANCES. 101 



in a disturbance of these operations, even though the constitution of the solid 

 tissues may have not yet been affected. As a general rule it may be stated, 

 that no Chemical action takes place between solid substances, and that they re- 

 quire to be dissolved in water or some other menstruum, before they can be made 

 to affect each other; and we find that this rule holds good constantly in the or- 

 ganized fabric, alike of Plants and of Animals. No alimentary material can be 

 appropriated by the organism, save in the liquid form; and hence it is that 

 Animals, whose food is solid, are endowed with a digestive apparatus for its 

 reduction to the state in which it may be absorbed by the sanguiferous and lac- 

 teal vessels, which answer to the rootlets of Plants, this state being either one 

 of complete solution, or of very minute division. No other liquid than Water 

 can thus act as a solvent for the various articles of food introduced into the 

 stomach. Again, it is Water which continues to form the solvent of the nutri- 

 tive materials, after they have found their way into the current of the circulation, 

 and have undergone that assimilating process which prepares them for being 

 applied to the renovation of the solid tissues; and, of the " vital fluid" which 

 courses in minute streams through nearly every part of the body, vivifying and 

 renovating the tissues which it traverses, water constitutes as much as from 76 

 to 80 per cent. So, again, it is the Water of the blood, which not merely brings 

 to the living tissues the materials of their development in a state ready for ap- 

 propriation, but also takes up the products of their disintegration and decay, and 

 conveys them, by a most complicated and wonderful system of sewerage, alto- 

 gether out of the system. It is not difficult to understand, then, how seriously 

 the chemico- vital operations of the body must be affected by 'a deficiency in the 

 normal proportion of this liquid, more especially as some of the substances to be 

 transported are of very difficult solubility ; and we find that the demand for it, 

 when it is withheld, soon becomes even more pressing than the demand for solid 

 food. It is remarkable that there are many Plants and even Animals, which 

 can be reduced to a state of complete inactivity by the desiccation of their tissues, 

 without the absolute loss of their vitality ; the usual condition of their bodies 

 being recovered, and their vital powers being restored, when they have been 

 allowed to imbibe an adequate supply of water. 1 



76. Of the solid inorganic components of the Human body, that which is 

 of greatest importance in regard to its amount and to the mechanical purposes 

 to which it is subservient, is Phosphate of Lime, or " bone-earth;" and there is 

 a strong probability that it is subservient also to very important purposes in 

 the chemico-vital operations of the economy. 3 It is in the Bones that this earthy 



1 See the Author's " Principles of Physiology, General and Comparative," p. 39, Am. Ed. 



2 "The constant occurrence of Phosphate of Lime in the histogenetic substances, and 

 especially in the plastic fluids," remarks Prof. Lehmann, "as well as its deposition in many 

 pathologically-degenerated cells of the animal body, obviously strengthens the opinion that 

 this substance plays an important part in the metamorphosis of the animal tissues, and 

 especially in the formation and in the subsequent changes of animal cells." (Op. cit. 

 p. 416.) This doctrine has been strongly advocated in a work entitled "Der Phosphora- 

 saure Kalk in physiologischer und therapeutischer Beziehung," (Gottingen, I860,) by Dr. 

 Beneke ; who has further maintained that, in various diseases which are characterized by 

 imperfect nutrition, the real source of the want of formative action lies in the deficiency of 

 this substance, which is carried out of the system in abnormal quantity, whenever an excess 

 of Oxalic acid is generated within it ; in proof of which he alleges that great benefit is de- 

 rived in such cases from the remedial administration of phosphate of lime, as well as from 

 the prevention of the formation' of oxalic acid, where this is possible. (See the "Proceed- 

 ings of the Royal Society," June 20, 1850.) It is remarkable that the glandular epithelium 

 of the mantle of certain Bivalve Mollusks, which seems to be specially concerned in the 

 formation of the shell, should be found to contain as much as 15 per cent, of phosphate of 

 lime, with only 3 per cent, of the carbonate, the remainder of their solid components being 

 made up of organic matter ; yet the shell itself contains no more than a trace of the phosphate. 

 (See C. Schmidt, " Zur vergleichenden Physiologic," pp. 58-60.) 



