158 MATERIA MEDIC A AND THERAPEUTICS. 



Characters. Colourless crystals, or white crystalline 

 masses, with a peculiar pungent odour, and a pungent, rather 

 bitter taste. Readily fused by gentle heat, recrystallising on 

 cooling to 120. Solubility, very freely in distilled water, 

 rectified spirit, and ether ; 1 in 4 of chloroform. 



Incompatibles. All alkalies. 



Impurities. Hydrochloric acid, detected by test-paper; 

 oily substances, colouring sulphuric acid when dissolved in 

 chloroform. 



Dose. 5 to 30 gr. 



Preparation. 

 Syrupus Chloral. 10 gr. in 1 fl.dr. Lose, \ to 2 fl. dr. 



ACTION AND USES. 

 1. IMMEDIATE LOCAL ACTION AND USES. 



Externally. Applied in weak solution (5 gr. to the ounce of 

 water), chloral hydrate is antiseptic; concentrated solutions 

 are irritant, causing vesication. The drug is but little used 

 externally. 



Internally. In the mouth and stomach it is also irritant 

 unless freely diluted, a point to be observed. It has no 

 specially sedative effect on the stomach or bowels like opium, 

 and therefore causes neither dyspepsia nor constipation. 



2. ACTION ON THE BLOOD. 



Chloral enters the blood as such, and probably leaves it 

 for the tissues without decomposition, although Liebreich, who 

 introduced it into the materia medica, contends that it is 

 broken up into chloroform and formic acid in the presence 

 of the sodium salts of the plasma. CoHCl 3 -f NaHO 

 NaCH0 2 -f CHC1 3 . The blood undergoes no appreciable 

 change. 



3. SPECIFIC ACTION AND USES. 



The action of chloral upon the system so nearly resembles 

 that of chloroform, and the chemical relations of the two sub- 

 stances are so close, that Licbreich's theory is at first sight 

 extremely plausible. Chloral chiefly affects the nervous 

 system, although one of the principal dangers connected with 

 its use depends on its direct action on the heart. Given in 

 moderate doses (20 to 30 gr.), hydrate of chloral, after a very 

 brief period of excitement, quickly induces drowsiness, followed 

 by several hours' sound sleep, natural in its characters and 

 refreshing in its effect ; as a rule, without consequent confusion, 

 headache, or drowsiness in healthy individuals. Larger doses 



