223 KEPORT— 1869. 



IX. The apparatus is not expensive in its first cost, and the cost of its main- 

 tenance is almost nominal. 



X. The system has had the advantage of being practically tested for more than 

 eighteen mouths upon an ordinary train running daily 250 miles and tested twenty- 

 two times each day ; and the result of this trial, as shown by the guard's daily 

 report, has proved the efficiency of its working as well as the ease and cheapness 

 of its maintenance. 



On the Penetration of Armour Plates hi/ Shells ivith Heavy Bursting Charges 

 Fired Ohliquely. By Sir Joseph Whitwoetf, Bart., LL.D., F.R.S. 



[Printed in extenso among the Reports, see page 430.] 



APPENDIX. 



Abstracts received too late for insertion in order. 



On the Physiological Action of Hydrate of Chloral. 

 By Benjamin W. Richardson, M.D., F.E.S. 



The following paper was drawn up by the desire of the President of the Biological 

 Section and tlie Department of Physiology during the Meeting. In opening the 

 subject, the author tirst expressed his thanks to Mr. Daniel Ilanbury, of Plough 

 Court, who had supplied him witli a specimen of the hydrate of chloral, and had 

 also been so good as to abstract from Liebreich's papers the piiucipal facts and 

 opinions on which the introduction of the hydrate into medical practice was based. 

 In brief, hydrate of chloral is a white crystalline body, soluble in water, and yield- 

 ing a solution not disagreeable to the taste. It is made by the addition of water 

 to the substance chloral. Chloral, the composition of whicli is C^IICl^ 0, is the 

 final product of the action of dry chlorine on ethylic alcohol. It is an oily fluid, 

 thin, colourless, volatile. The specific gTavity is 1-502 at 64° Fahr., and it boils 

 at 202' Fahr. It has a vapour-density of 7-"j, taking hydrogen as unit}'. The odour 

 is pungent. When chloral is treated witli a little water, heat is evolved, and small 

 stellate white crystals are formed as the fluid solidifies. The solid substance is the 

 hydrate of chloral, C, IICl^ OIL, 0. The hydrate is slowly volatilized if it be ex- 

 posed to the air, and tlie odour of it, were it not pungent, is so like melon as to be 

 hardly distinguishable from melon. When heat is applied to the hydrate, it distils 

 over without undergoing decomposition. 



When to a watery solution of hydrate of chloral caustic soda or potassa is 

 added, the hydrate is decomposed, chlorofonn (CHCl.,) is set free, and a formate 

 of sodium or potassium, according to the alkali used, is formed. It was on a 

 knowledge of this decomposition by an alkali that Liebreich was led to test the 

 action of the substance physiologically. lie conceived the idea that in the living 

 blood the same change could be effected, aud that the chloroform would be libe- 

 rated so slowly that ana3sthesia of a prolonged kind would result. To try this, he 

 subjected animals to the action of chloral, and even man, and proved that sleep 

 could be rapidly induced without the second stage of excitement common to the 

 action of chloroform when it is given by inhalation. Liebreich produced in a 

 rabbit, by a dose of 0'5 grm. of the hydrate of chloral, a sleep which lasted nine 

 hours. This dose was equivalent to 0'35 of chloral, and to 0'29 of chloroform. 

 The symptoms, he found, were like those produced by chloroform. In some cases 

 he gave the hydrate to the human subject. The first case was that of a lunatic, to 

 whom he administered 1'35 grm. Xo irritation was set up, and five hours of 

 sleep was obtained. In a second case, he gave internally a dose of 3'5 grms. to 

 a man suftering from melancholia, by which he produced a sleep of sixteen hours. 



