496 DISEASES OF THE URINARY ORGANS. 



the earthy inspissations, are soft like paste, but grow firm 

 towards the centre. The' second kind are yellowish or whitish 

 calculi, with rugged, grained, or simply fretted surfaces, com- 

 posed of an irregulM* mass of more or less coherent saline 

 material. Some present areolated interiors, and exhibit 

 different degrees of hardness in their composition. The third 

 kind are formed of concentric plates, and are void of any cen- 

 tral nuclei ; they are commonly gray, fretted upon their sur- 

 faces, and harder than the foregoing sorts. In some of these 

 the saline materials are found much less compact in the centre 

 than towards the circumference. The fourth kind is the cal- 

 culus with nucleus ; of which there occur two varieties : one 

 composed of concentric plates, as hard almost as flint, with 

 a wall-like kind of surface ; the other less compact, with a 

 granulated exterior and a diversified areolated interior. 



In the year 1839, Mr. G. Baldwin forwarded to the 

 Veterinary Association (then in existence) a quantity of 

 subulous matter weighing eight pounds and a half, which he 

 had taken from the bladder of a horse, destroyed for old age. 

 During life no urgent symptoms presented themselves ; the 

 animal was observed to urinate frequently, and sometimes 

 the urine would be interrupted in its flow. 



Chemical Composition. — Urinary calculi taken from 

 horses have been found by Fourcroy and Vauquelin to be as 

 remarkable for the uniformity of their composition as those 

 obtained from the human body have proved for their strange 

 diversity and variety in this respect. Classifying human 

 urinary calculi according to their .diff'erent constituents, no 

 less than eleven kinds are described as being at times met 

 with; whereas, in horses, taking the same mode of classifica- 

 tion, no more than one kind can be said to be produced. 

 Horses' calculi have proved uniformly to consist of carbonate 

 of lime, and a very small proportion — one-hundredth part — 

 of carbonate of mapiesia, mixed up and cemented together 

 by an animal matter found to be mucus, mingled in some 

 cases with albumen. " By far the greater number of calculi 

 found both in the horse and ox are composed principally of 

 the carbonate of lime and animal matter. In a few I have 



