SALTS. 47 



obtained from the body of the mother, first by imbibition from the 

 mucus of the Fallopian tube by the vitelline membrane, then by the 

 villi of the chorion, and when these become vascular, after the de- 

 velopment of the allantois, they derive it from the mother's blood 

 till birth. Subsequently it enters the blood from the alimentary 

 canal, having entered the latter with the food, or as a beverage ; 

 accidentally entering, also (as in bathing), by the skin. The aggre- 

 gate amount of water consumed as drink by an adult male in a year 

 is about 1,500 pounds. M. Barral finds that more water leaves the 

 body than enters it, and maintains that the surplus is formed in the 

 body by the combination with hydrogen of the oxygen in the in- 

 spired air, and the excess of oxygen over the hydrogen in our ali- 

 ment. 



Uses of Water in the Body. It gives to organic substances their 

 mechanical properties, to fluids their fluidity, to derni-solid sub- 

 stances their elasticity and particular consistence; and different 

 properties to the hard parts to cartilage its flexibility, to bone its 

 tenacity. But in the last the water is more intimately united, and 

 being once separated, will not unite again. Water gives to all parts 

 the possibility of manifesting their chemical properties also, and 

 hence that instability characteristic of organized tissues, and the 

 constant acts of combination and decomposition. But it also, with 

 these advantages, confers the liability to sudden changes in the 

 blood, or in the organs, from putrid, purulent, or mephitic infec- 

 tions, facilitates the transmission of poisons, procures the aptitude 

 to decomposition, and hence, in many cases, induces sudden death. 1 



The water makes its exit from the body by the kidneys and the 

 skin, in the feces, and from the pulmonary mucous membrane. 

 About 1,900 pounds escape annually through these outlets, the 

 urine alone containing 900 pounds. The fact that 400 pounds more 

 of water are excreted than are ingested as drink is accounted for, 

 in part, by M. Barral, as already stated; while it must be recollected 

 that our food, also, always contains more or less water. 



SECOND DIVISION. 

 The Saline Principles Salts. (19.) 



The salts contained in each tissue are represented by the ashes 

 resulting from its combustion pretty nearly, but not precisely, since 



1 Robin and Verdeil. 



