S98 VEGETABLE DEUGS 



urine, after the subcutaneous injection of small doses of 

 caffeine. This effect is independent of the general vascular 

 condition, and is followed by an increase in the volume of 

 the kidneys, with accompanying augmentation of the urinary 

 secretion, as shown by experiments with Roy's oncometer. 

 The renal cells are directly stimulated, and it is thought that 

 caffeine also increases the blood supply of the malpighian 

 bodies. The drug is therefore a local diuretic and (with 

 theobromine) is the most efficient and powerful. ISTo other 

 drug can jDroduce such a flow of urine. 



Respiration. — The respiratory centres are stimulated 

 (along with the vagus and vasomotor) by caffeine in mod- 

 erate doses, and depressed by toxic amounts. 



Metabolism. — Caffeine increases tissue change and 

 therefore the elimination of urea and carbonic dioxide — con- 

 trary to the time honored teaching. 



Toxicology. — Caffeine is a spinal and muscle poison to 

 the frog. Tetanic convulsions occur in the batrachian sim- 

 ilar to those produced by strychnine, but there is also mus- 

 cular rigidity. These phenomena follow the direct stimula- 

 tion of the spinal motor tract and muscles, and are succeeded 

 by paresis. In man, stimulation of the cerebral cortex oc- 

 curs, while both stimulation of the brain and cord are ob- 

 served in the domestic animals. The symptoms of poison- 

 ing in dogs, cats and mammals generally, are restlessness, 

 occasionally vomiting in dogs, rapid breathing, primary re- 

 duction followed by rise in temperature, clonic or tonic 

 convulsions, muscular weakness, and general paresis. Death 

 occurs from respiratory failure. The minimum fatal dose 

 is about 1 gr. to 1 lb. of live weight in the cat. 



Administration. — Caffeine and its ordinary salts are 

 decomposed by water and therefore should not be given sub- 

 cutaneously. The alkaloid is best administered in solution 

 with sodium salicylate, or benzoate, for use under the skin 

 as follows : — 



Caffeinse gr.xl. 



Sodii salieylatis gr.xxx. 



Aquae 3 i. 



M. 



S. Give fifteen drops hypodermically to horse. 

 Three drops to dog. 

 or : — 



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