56i THE DISEASES OF THE HORSE 



CALCULI IN THE BOWELS 



A STOPPAGE IN THK HOWKLS .soinetimos obstinately persists, in spite of all 

 kinds of remedies, and, death taking place, it is found on examination that 

 a large calculus has blocked up the area of the canal. Sometimes one of 

 these calculi is found in the stomach, but this is extremely rare. On making 

 a section they are found to consist of concentric layers of bran, chaff, and 

 other hard particles of the food, mixed generally with some small proportion 

 of earthy matter, and arranged around some foreign body, such as a piece 

 of stone from the corn, or the head of a nail. Treatment is out of the 

 question, as it is impossible to discover the calculus during life, and even if 

 it could be ascertained to exist, no remedy is known for it. Those who are 

 curious about the composition of these calculi, will be pleased with the follow- 

 ing letter by Mr. Buckland, surgeon to the 1st Life Guards, in reply to an 

 inquiry made in The Field as to the composition of a calculus found in a 

 horse belonging to a correspondent : — 



" Mr. C. Pemberton Carter having, in his interesting letter, requested me 

 to throw some light upon this subject, I have great pleasure in giving what 

 little information I am able to afford, with apologies for delay, as Aldershot 

 camp is by no means a favourable spot for scientific investigations or literary 

 pursuits. As regards the actual composition of calculi such as he has sent, 

 we learn from the catalogue of the museum of the Royal College of Surgeons 

 that they are composed for the most part of the phosphate of magnesia and 

 ammonia, with small quantities of phosphate of lime. They also contain an 

 animal and extractive matter, to which the brown colour of tlie calculus is 

 Q-sving. They also contain muriates of soda, and various alkaline salts derived 

 from the intestinal juices. The animal matter resembles that of all other 

 concretions, and separates in concentric laminae when the calculus is dissolved 

 in an acid. In moi-e impure varieties, grains of sand, portions of hay, straw, 

 etc., are frequently found embedded in the calculus, and there is one specimen 

 in the museum which contains an entire layer of vegetable hairs. Mr. 

 Carter remarks that ' his impression is that the calculus is made up of bran ' 

 (chemically speaking). He is not far wrong, for we read in the College 

 catalogue, ' Most authorities agree that these calculi are formed from 

 phosphate of magnesia, contained in wheat, oats, hay, etc., and this opinion 

 derives confirmation from the circumstance that they occur most frequently 

 in millers' and breicers' horses, which are fed upon grains, bran, and sub- 

 stances known to contain a much larger proportion of magncsian salts than 

 other vegetable matters.' Mr. Carter has detected minute portions of wheat, 

 oats, and hay in the calculus, which therefore may be said to consist of two 

 substances, viz. the vegetable and the mineral. So much, then, for the 

 composition of the calculus ; now for its mechanical structure. Most 

 decidedly it may be compared to an onion, layer being packed over layer, so 

 as in section to present a ringed appearance. We ma}' also liken it to 

 other objects. It has lately struck me to examine the structure of a common 

 cricket-ball, which combines hardness, lightness, and elasticity in such an 

 admirable way. Upon making a section, I found the cricket-ball to be 

 composed of layers, one over the other, round a central nucleus. The layers 

 are composed of leather, alternated with a vegetable fibre, the nucleus being 



