336 EXCRETION 



tially the same as in the male, with the exception of the slight modifica- 

 tions due to differences in the direction and length of the urethra. 



According to Budge, the influence of the nervous system on the 

 bladder operates through the sympathetic ; and he has described a 

 centre in the spinal cord, which presides over the contractions of the 

 lower part of the intestinal canal, the bladder and the vasa deferentia. 

 This is called the genito spinal centre, and it has been located, in experi- 

 ments on rabbits, in the spinal cord, at a point opposite the fourth 

 lumbar vertebra. From this centre the nervous filaments pass through 

 the sympathetic nerve, communicating with the ganglion which corre- 

 sponds to the fifth lumbar vertebra. 



PROPERTIES AND COMPOSITION OF THE URINE 



The color of the urine in the human subject is quite variable within 

 the limits of health and depends to a considerable extent on the char- 

 acter of food, the quantity of drink and the activity of the skin. As a 

 rule the color is yellowish or amber, with more or less of a reddish tint. 

 The liquid is perfectly transparent, free from viscidity, and exhales, 

 when first passed, a peculiar aromatic odor that is not disagreeable. 

 Soon after the urine cools, it loses this peculiar odor and has an odor 

 known as urinous. This odor remains until the liquid begins to undergo 

 decomposition. The color and odor of the urine usually are modified by 

 the same physiological conditions. When the urine contains a large 

 proportion of solid matters, the color is more intense and the urinous 

 odor is more penetrating ; and when its quantity is increased by an ex- 

 cess of water, the specific gravity is low, the color is pale and the odor is 

 faint The first urine passed in the morning, immediately after rising, 

 usually is more intense in color than that passed during the day and 

 contains a relatively larger proportion of solids in solution. 



The temperature of the urine at the moment of its emission, under 

 physiological conditions, varies but a small fraction of a degree from 

 100 Fahr. (37.78 C). 



In estimating the total quantity of urine discharged in the twenty- 

 four hours, it is important to take into consideration the specific gravity 

 as an indication of the amount of solid matter excreted by the kidneys. 

 Variations in quantity constantly occur in health, depending on the 

 proportion of water ; but the quantity of solid matters excreted usually 

 is more nearly uniform. It must also be taken into account that 

 differences in climate, habits of life etc., in different countries, have an 

 important influence on the daily quantity of urine. Parkes collected 

 the results of twenty-six series of observations made in America, Eng- 



