ASTRINGENTS 259 



40 mils; large dogs, 100—200 mils; small ruminants, foals and 

 calves, 200 — 400 mils; horses and cattle, 2000—3000 mils. 

 (Jacob.) 



It should be remembered that the mucosa of the rectum can only 

 change starch and saccharose into glucose, but has considerable ab- 

 sorptive powers, and may therefore absorb water, salts, glucose, pep- 

 tone, albumoses and other albuminoid bodies and small amounts of 

 emulsified fats. The best adapted for dogs are milk, starch, glucose 

 and raw eggs. The amount of glucose should not be over 2 per cent., 

 of starch 8 — 10 per cent, of the total amount. 



This enema is prepared by stirring starch and cold water and 

 pouring this into boiling water in order to pro.duce a starch jelly. 

 To this is added glucose, previously dissolved in hot water. Finally 

 two or three eggs stirred up in a little water and salt are slowly 

 mixed with the cooled starch paste under constant stirring to insure 

 a uniform mixture. 



The digestion and absorption from the rectum of herbivora have 

 not been studied with reference to the exact metabolism., Hutyra 

 and Marek. 



Eectal suppositories are made of soap, glycerin, wheat-gluten 

 and plain or medicated cocoa butter. The evacuant suppositories act 

 largely mechanically as a foreign body, stimulating the rectum to 

 expel it. A piece of ice or an undisintegrated piece of soap will 

 have the same effect. Those made of almost pure glycerin with 

 enough sodium stearate to give a solid consistence are much used. 

 According to Hertz, the glycerin acts as an irritant to the anal canal 

 but not to the rectum. 



Suppositories are most useful when the feces come back to the 

 rectum but are retarded in their expulsion by a tight or sensitive 

 sphincter. 



8. ASTRINGENTS 



Astringents are agents which cause constriction of the tissues by 

 direct action. This action is largely due to the fact that they form 

 compounds with the tissue elements which are soluble only under cer- 

 tain circumstances. In this way they precipitate albumen as the albu- 

 minate, tannate, etc. Some of these albuminates are insoluble in 

 water, some soluble in an excess of the proteid, while the tannates are 

 insoluble in water, but soluble in an excess of albumen, gelatin, or in 

 acetic and lactic acids. The action of the astringents is most marked 

 upon mucous membranes or raw surfaces. Some of them also have 

 the power to check the secretions of glands, which is chiefly due to 

 coagulation or precipitation of the proteids of the cells and some 

 shrinkage of the cells by direct action. There may be some action 



