32 SYNOPSIS OF VETERINARY 



tain and re-absorb water. One function may be stimulated with- 

 out the other; certain diuretics stimulate the excretion of water, 

 while others stimulate the excretion of the solid constituents. 



Diuretics. — Are divided into direct and indirect. A direct 

 diuretic stimulates the renal cells, and an indirect diuretic acts 

 by augmenting blood pressure. 



i. Refrigerant Diuretics. — Those which act by reducing the 

 force of the circulation ; as, water in large quantities, potas. salts, 

 especially acetate, bitartrate, chlorate, citrate and nitrate. These 

 also operate on the cells and increase the amount of solids ex- 

 creted. 



2. Hydragogue Diuretics. — Largely increase the watery 

 constituents of the urine, and in general act by raising arterial 

 pressure, either general throughout the body or locally in the 

 kidneys. 



This is accomplished in two ways, directly and indirectly ; 

 indirectly, by increasing heart's action ; directly, by contracting 

 efferent vessels so as to raise the pressure in the glomeruli and 

 dilate the afferent vessels. This is done by colchicum, digitalis, 

 nitrous ether, strophanthus and alcohol. 



3. Stimulant Diuretics. — Are largely eliminated by the kid- 

 neys and act upon the entire genito-urinary mucous membrane by 

 local irritation, and in excessive doses may excite inflammation 

 and symptoms of a violent character, as strangury, bloody urine, 

 etc. (all this group should be used with caution) cantharides, 

 turpentine, juniper, uva ursi, buchu, savin, copaiba and hydran- 

 gea ; these act on the secreting cells of the tubules. 



Diuretics are Used. — First, to increase the proportion of 

 water in the urine, thus preventing deposits of solids in the kid- 

 neys or bladder and mechanically washing them out when formed 

 or in other words to dilute the urine ; second, to expel waste pro- 

 ducts and poisonous material from the system, as in febrile or 

 rheumatic disorders, or where kidneys are acting tardily ; third, to 

 remove excess of fluid from the tissues or serious cavities, as in 

 dropsy of the. chest and abdomen, oedema of legs, etc., this ex- 

 cess of fluid (serum) may be due to disease of the heart, kidneys, 

 liver, and as a result of inflammation of a part ; fourth to over- 

 come an acid' condition of urine, in which give saline diuretics. 



