196 DEPRESSANTS TO PERIPHERAL NERVES 



DRUGS USED TO PARALYZE TASTE ORGANS 



There are several drugs that paralyze taste which it seems well 

 to describe here. 



Gymnemic acid (from Gymnema sylvestris). Destroys bitter 

 and sweet, not acid or salt. 



Eriodictyon (Yerba santa), the leaves of Eriodictyon glutinosum, 

 native to California. Destroys bitter taste; not sweet, acid or salt. 

 The fluid extract is mostly used. One mil will cover the taste of 

 0.012 gm. of quinine sulphate or 1.5 gm. of quassia. It is probably 

 therapeutically objectionable, because it may render alkaloids in- 

 soluble on account of the tannic acid it contains. Furthermore, it is 

 believed that the action of bitters as such depends somewhat upon the 

 bitter taste. 



MOTOR NERVE DEPRESSANTS 



A few drugs depress the peripheral nerves but are of more im- 

 portance from the standpoint of toxicology than medicine. The most 

 important are: 



Hydrocyanic acid 



Cyanides 



Crude drugs from which hydrocyanic acid may be obtained 



Wild Cherry and bitter almonds 



Curare 



Conium 



Gelsemium 



Lobelia 



Tobacco 



ACIDUM HYDROCYANICUM DILUTUM — DILUTE HYDRO- 

 CYANIC ACID 



Diluted prussic aci/i is an aqueous solution containing 2 per cent, 

 by weight of absolute hydrocyanic acid. It should be kept in small 

 bottles well protected from light in a. cool place. Scheele's hydro- 

 cyanic acid contains about twice the amount of the official prep- 

 aration. 



Doses. Horses and Cattle. 1T\, xx — .^j ; 1. — i. Sheep. Tt\ 

 X — XV ; 0.6 — 1. Dogs. 111, j — iij; 0.06 — 0.2. 



Action. Hydrocyanic acid is a protoplasmic poison. It para- 

 lyzes the sensory nerve endings, causing local anesthesia. 



Digestive System. When administered in fairly strong con- 

 centration, hydrocyanic acid causes a feeling of burning in the 

 mouth with a reflex increase of saliva, followed by numbness and 



