THE VASCULAR GLANDS. 81 



of urea excreted. The secretion of urea continues if nitrogenous 

 food be absent from the diet ; and the elimination is increased by 

 increased cell-activity, and. consequently, of cell-degeneration, as 

 by muscular work. 



What is the amount of urea excreted? 



The amount varies, but it may be considered to be about one- 

 half the solid constituents of the urine. Roughly speaking, the 

 urinary solids may be regarded as 4 per cent, of the total, and 

 the urea (including the uric acid and urates) about 1.5 to 5 per 

 cent. This proportion is very variable, and there may be urea in 

 healthy urine to exceed 2 $ per cent., or in a much less ratio than 

 5 per cent. 



Method of Estimating Solids. A useful rule for approximately 

 estimating the total solids in any given specimen of healthy urine 

 is to multiply the last two figures representing the specific gravity 

 by 2.33. Thus, in urine of sp. gr. 1025, 25 X 2.33 = 58.25 gr. of 

 solids in 1000 gr. of urine. In using this method it must be re- 

 membered that the limits of error are much wider in diseased than 

 in healthy urine. 



What abnormal matters are sometimes found in urine ? 



In disease or after the introduction of certain foods we may find 

 certain abnormal elements in urine serum-albumin, globulin, fer- 

 ments, peptone, blood, sugar, bile acids and pigments, casts, fats, 

 micro-organisms, etc. 



THE VASCULAR GLANDS. 

 What is meant by the term "vascular glands"? 



Certain glandular organs which are made up largely of lym- 

 phatic tissues, but which do not seem to be connected, at least 

 directly, with secretion or excretion. Among these glands may be 

 mentioned, as the more noticeable, the spleen, the thymus gland, 

 the thyroid gland, the tonsils, the suprarenal capsules, the pineal 

 and the pituitary glands, and Peyer's glands. 



What, in a general way, is the function of the vascular glands ? 



This cannot be fully answered, as the subject is not understood 

 at all completely ; but it may be said that their work has probably 

 to do with the elaboration of the blood, and, further, that each of 



6-^Phy. 



