GLANDS. 461 



mulated fat ; and in this particular his views differ from those already 

 cited of Dr. George Johnson. 



The volume and weight of kidneys containing exudation in the tubes 

 are frequently much increased. 



The exudation may be diffused throughout the organ, or it may be 

 confined to certain portions of it. " It then tends," writes Dr. Gairdner, 

 " to accumulate in certain sets of the convolutions in which the urinary 

 current is least active. These becoming partially blocked up, and ceasing 

 entirely to secrete, are thrown aside from the outward current of se- 

 cretion, and become a centre of attraction for further deposit, just as 

 the eddies arid still waters at the sides of a rapid stream receive from 

 it the foam and floating bodies brought down from above. In this way, 

 more and more of the adjacent loops of tubuli are filled with the ab- 

 normal deposit, and become added to the former nucleus, until the 

 masses of exudation, thus imprisoned within tubules through which no 

 secretion passes, form irregularly rounded bodies in the cortical sub- 

 stance, visible to the naked eye, more or less prominent on the surface of 

 the organ, and usually of an opaque yellowish colour. These are the 

 granulations first described by Dr. Bright." 



Intratubular exudations, excluding tubercular and cancerous deposits, 

 may be considered under three heads : a, crystalline or saline matters 

 deposited from the urine ; b, oleo-albuminous, or granular exudations 

 from the blood plasma ; c, exudations forming pus. 



a. The most common saline deposit met with in the tubes of the 

 kidney is the amorphous urate of ammonia ; inasmuch as this salt is a 

 constituent of healthy urine, its presence in moderate quantities is 

 merely a normal post-mortem appearance, the deposition of the salt 

 resulting from the cooling of the urine after death. In some instances, 

 however, it is present in such large quantities ; and in these it occasions 

 such an alteration in the appearance of the kidney, that it might, unless 

 discriminated by means of the microscope, be attributed to disease. 



Under the microscope, the urate of ammonia presents the appearance, 

 when within the tubes, of a fine molecular shading, which entirely ob- 

 scures the nuclei ; the distinguishing character of this deposit is its 

 ready solubility in the dilute acids, as the acetic or nitric. 



In one case Dr. Gairdner detected the presence of crystals in the tubes, 

 which, from their appearance and colour, he entertained little doubt 

 were of uric acid, although, from their minute quantity, they could not 

 be submitted to chemical examination. 



In this case the urine was of low specific gravity, and albuminous, 

 although there was no apparent exudation within the substance of the 

 gland. 



b. Dr. Gairdner includes under the term " oleo-albuminous exuda- 

 tions from the blood plasma," those exudations which are fatty in their 

 nature, as well as the inflammation globules, granular corpuscles, or 

 exudation granules, and corpuscles of different writers. 



p r 2 



