J282 



URINE. 



of morbid change in important organs, from 

 such as may merely be the results of actions 

 occurring in perfect health, and consistent 

 with its preservation. 



Many pathological conditions of the urine 

 are indeed closely simulated by the unim- 

 portant changes to which I have alluded. 

 Thus the urine of diabetes insipidus, often a 

 most severe and unmanageable disease, can 

 scarcely be distinguished from that occasionally 

 secreted by healthy persons exposed to cold 

 or moisture, or both, without sufficient exer- 

 cise to maintain the full amount of cutaneous 

 exhalation. Such a specimen, were it ex- 

 amined carelessly, or allowed to guide the 

 judgment without due attention to con- 

 comitant circumstances and previous history, 

 might lead (and I may say has led) to mis- 

 takes both injurious to the patient and vexa- 

 tious to the practitioner. 



In studying the pathology of the urine, it 

 is also especially important that we should 

 not give undue regard to chemistry, nor be 

 led astray by theories and generalisations such 

 as that fascinating science so constantly 

 would tempt us to enter upon. It must be 

 remembered that in most cases chemistry as 

 yet only assists us in the detection of symp- 

 toms, and in the present state of our know- 

 ledge can only thus far serve us, but must 

 fail as a guide to a true knowledge of diseased 

 action or appropriate methods of treatment. 

 This consideration, however, is far from de- 

 pressing to those who regard the subject in 

 a truly philosophical spirit ; for be it remem- 

 bered that when we have detected sugar or 

 albumen in the urine, and when the modes of 

 examination are rendered both easy and exact 

 by chemical labour, we have reaped a most va- 

 luable advantage by becoming acquainted with 

 a symptom, without which, we should have 

 been left in such a position that we might have 

 despaired of ever obtaining an insight into 

 the pathology of two most important diseases. 

 A knowledge of symptoms thus acquired by 

 chemistry at once enables us to make use 

 of a large amount of valuable information 

 derived from experience, and to bring to our 

 assistance remedies which would not other- 

 wise have suggested themselves, or perhaps 

 have been considered inapplicable. It has 

 unfortunately too often been attempted to 

 push chemical reasoning to the uttermost in 

 considering urinary diseases ; and there is a 

 class of persons, greatly increasing in the 

 present day, who have thus inflicted much 

 mischief on a science which requires great 

 labour in its prosecution, and consequently 

 is the more eagerly condemned as useless by 

 the idle or ungifted practitioner. If we con- 

 fine the application of chemistry, in urinary 

 disease, merely to symptomatology, it is easy 

 to show that we are deeply indebted to the 

 science, and it is the especial duty of those 

 who are most conversant with it to regard 

 its further application with great jealousy. 



I shall now proceed to describe the urine 

 as it appears in various diseased conditions of 

 the body, beginning with those variations 



from healthy constitution characterised by 

 the existence of deposits of various kinds 

 known as urinary deposits. It is not, how- 

 ever, within the province of this article to 

 enter upon any pathological considerations 

 relating to these abnormal conditions. 



LITHIC ACID DEPOSIT. 



This deposit (commonly known as "red 

 sand" or gravel) occurs in urine in many 

 forms, the crystals as seen under the micros- 

 cope presenting the appearances figured below 



Fig. 791. 



Q 



Urine depositing lithic acid is generally of 

 a deep yellow colour, and acid beyond the 

 normal degree. Its specific gravity is mostly 

 somewhat above that of health. Lithic acid 

 occasionally deposits from urine in an amor- 

 phous concrete form, and is seen in rounded 

 or flattened masses adhering to the bottom 

 of the chamber vessel. This latter kind of 

 deposit is the most dangerous as respects the 

 formation of calculi. 



DEPOSIT OF LITHATES. 



This form of deposit, known as the lateri- 

 tious deposit, from ts resemblance to brick 

 dust, consists of lithic acid combined with 

 ammonia, and in some few cases with lime, 

 magnesia, or soda. The microscopic appear- 

 ances shown by the lithates are as under 

 (/g. 792). 



Fig. 792. 



The spheroidal masses with projecting needle 

 points (B), I believe to indicate lithate of lime, 

 while the masses having projecting crystals 

 with truncated ends (c), 1 believe consist 

 chiefly of lithate of magnesia. The lithate of 

 ammonia is amorphous, sometimes spheroidal 

 with adhering spicula, or is seen making up 

 a dotted background (A). Urine depositing 

 the lithates is generally of a higher specific 

 gravity than natural, and is passed clear. 

 After the deposit has occurred, the applica- 

 tion of a gentle heat is always sufficient to 

 re-dissolve it. 



