96 VETERINARY MEDICINE AND SURGERV. 



'' Superpurgation does not always depend upon the strength of the 

 dose. In some instances as little as four drachms of aloes have been suc- 

 ceeded by fatal consequences. Again, horses in an obese condition, and 

 those suffering from slight colds, are easily acted upon by purgative med- 

 icines, and are apt to sink from superpurgation. A full dose of aloes, 

 from six to eight drachms, operating quickly, is seldom succeeded in 

 healthy animals by any evil consequences; the same quantity, however, 

 if divided into two or more doses, has a much more depressing effect, and 

 is apt to be followed by serious consequences. In the first instance, the 

 quantity, by its strength, insures its own expulsion; Avhilst in the second, 

 the aloes is absorbed into the circulation, excites a toxic effect upon the 

 system generally, and reduces the horse to such a state of debility that 

 it succumbs to the purgative influence. The explanation of the tendency 

 to superpurgation in the horse is to be found in the fact that its bowels 

 are extremely vascular in comparison with those of other animals, and 

 that the effect of the purgative acting upon so vascular a surface is grave 

 and serious. I have already pointed out that many young horses, when 

 first brought into the stable, are rendered susceptible to various diseases 

 by the debilitating influences of indiscriminate purging, and that such a 

 method of treatment is uncalled for and irrational. In addition to the 

 symptoms described by Messrs. Haycock and Field, I have observed that 

 those of laminitis are induced by purgatives, and that when they occur 

 they indicate a condition of great gravity. 



" The post-mortem appearances are those of congestion of the intes- 

 tinal mucous membrane generally, concentrated in many cases in that of 

 caecum caput coli; a thick, tarry appearance of the blood, and extreme 

 blackness, congestion or apoplexy of the lungs, the blood being, as it 

 were, deprived of its watery elements, altered in its composition, ren- 

 dered too viscid to circulate through the pulmonary capillaries, and so 

 altered chemically as to be rendered unfit for perfect oxidation. 



*' In order to prevent the occurrence of superpurgation after the ad- 

 ministration of an aloetic, or, more particularly, a mercurial and aloetic 

 purgative, it is necessary that the practitioner should order the animal to 

 be fed on an easily digestible diet, such as warm bran mashes; that the 

 quantity of water should be restricted, and that the chill be taken off it, 

 for nothing is so apt to induce inordinate intestinal action as large quan- 

 tities of cold water whilst the animal is in physic. It is also necessary 

 that no green food, roots, or other articles of diet, containing much 



