406 REPOET — 1869. 



can be induced in from twenty to forty seconds, with perfect recovery in from 

 three to five minutes. The mode of administering, in order to produce these 

 effects, is simple : the inhaler I showed last year is modified by being 

 lengthened, and the fluid is not introduced as spray, but is poured directly 

 into the inhaler. The inhaler itself is made of leather, and is lined with 

 loose demette ; it is jjerforated at the end furthest removed from the mouth, 

 so as to admit air. For this modificatiou of inhaler, and for demonstrating 

 the extremely rapid action of the bichloride with it on the human subject, we 

 are indebted to Mr. Rendle. The method has been successfully employed 

 now in four hundi'ed operations. I may be pardoned for dwelling on this 

 practical fact for one reason alone ; for this reason, that it shows the true 

 value of a correct theory in estimating the properties of chemical substances 

 on living animal bodies, based on the physical characters, purely, of the sub- 

 stances themselves. From the chemical composition of the bichloride of 

 methylene, from its boiling-point, and the density of its vapour, I was able 

 to claim for it its probable place as an anesthetic before it was subjected 

 to the test of experience, and especially to claim for it that its power to take 

 effect would be as rapidly developed as would be the recovery from it when 

 it was withdrawn. The practice has proved the theory to have been in this 

 case safely founded ; and the fact may be accepted as an encouragement to all 

 who are or may be striving to reduce oiu- knowledge of the action of 

 medicinal agents to fixed principles. For my part I am certain (and I think 

 the after pages of this Report will help to prove the idea) the day is at 

 hand when the mere chemical and physical characters of any substance being 

 known to the physiologist, he wUl be able to foresee clearly what are the 

 physiological values of the substance, and to calculate the symptoms and 

 changes it will induce in the animal economy from pure theoretical formulas 

 and with perfect precision. 



Methtlal. 



The substance methylal, C3 fl, 0.,, to which I called attention last year, 

 deserves another brief word. I confirm what I said concerning it last year, 

 viz. that it is a slowly acting anaesthetic, producing by its inhalation a sleep 

 which is very deep and prolonged. I would add to this Report that methylal 

 may be taken internally in the same proportion as common ether (it could be 

 used also in the form of hypodermic injection), and that, as it is soluble in 

 water, it promises to be a very valuable addition to our list of anodyne 

 remedies. During the past months Liebreich of Berlin has brought out the 

 substance chloral (C^ H CI3 0) as a body which possesses the power of inducing 

 long-continued sleep. I have not yet been able to obtain chloral for ex- 

 periment *. 



PLAN OF NEW RESEARCHES. 



In the new researches to which I have devoted my attention since last 

 Meeting, I have aimed, while studying the action of several compounds which 

 have not previously been considered by the physiologist, to bring the present 

 work, together with the past, into sj'stematic arrangement, to group under 

 their proper chemical heads the agents submitted to inquiry, and to ascertain 

 whether any distinctive physiological characteristics could be discovered as 

 connected with distinct chemical series of organic bodies. I commenced, 

 therefore, by placing before myself a set of Tables which I now put before the 



* After the reading of this Report Dr. Richardson was supplied, at Exeter, with a spe- 

 cimen of chloral by Daniel Hanbury, Esq. He was thus enabled, at the request of the 

 Section, to bring up a supplementary report on chloral during the Meeting. 



