ITS QUANTITATIVE RELATIONS. 419 



either in my own urine, or in that of other healthy persons, during 

 an ordinary or even an exclusively animal or vegetable diet. The 

 influence of the food upon the quantity of earthy phosphates in 

 the urine is, however, undeniable ; while, living on a purely animal 

 diet, I found that my urine contained nearly three times as much 

 earthy phosphates as when living on a mixed diet. The urine of 

 young children, like the altantoic fluid of calves, contains only 

 very small quantities of phosphates, but a comparatively large 

 amount of sulphates. It is probably for some similar physiological 

 reason that pregnant women secrete far less phosphate of lime 

 with the urine than non-pregnant ones, a fact that has been pre- 

 viously mentioned. 



These few illustrations are sufficient to indicate the numerous 

 conditions on which the quantities of the urinary constituents and 

 their various proportions to one another are dependent, and to 

 show the caution we should exercise in forming an opinion on the 

 nature of a specimen of urine, or in drawing any conclusions on 

 the point, unless we have numerous analyses of different urines 

 collected under similar conditions. 



The next point which it is necessary for us to notice, is the 

 difference in the urine in the two sexes. From the experiments 

 of Lecanu and Becquerel, to which we have already alluded, it 

 appears that the chief difference is, that the urine of women con- 

 tains more water and less urea and salts, even " in relation to the 

 other solid constituents ; that is to say, women discharge absolutely 

 more water and far less urea and salts than men, while the quantity 

 of uric acid appears to be about the same in both sexes. 



The urine of women in a state of pregnancy presents certain 

 marked peculiarities, of which the most distinguishing, namely, the 

 formation of the substance called kyestein, has been already noticed 

 in p. 426. Becquerel found that the specific gravity during preg- 

 nancy never exceeded 1*011. According to Lubanski,* such urine 

 contains less than the ordinary quantity of free acid, and is fre- 

 quently neutral or even alkaline; as far as my own experience 

 goes, it is, however, always acid when freshly passed, if the women 

 are in good health, but during the latter months of pregnancy it 

 very readily becomes alkaline, since it then generally becomes 

 more aqueous. We have already alluded to the relative and abso- 

 lute diminution of the phosphate of lime in the urine of pregnant 

 women. 



We are indebted to Lecanu for most of our knowledge regarding 



* Ann. d'Obstetr. &c. 1842, p. 235. 

 VOL. II. 2 G 



