PHVSIOLOGICAL ACTIOiil OF OKGANIC CHEMICAL COMPOUNDS. 149 



longer time, would be serviceable in sustaining a slight narcotism. It is pro- 

 bable that in some chronic diseases of the throat or bronchial passages, where 

 the effect of a local narcotic would be desirable, this mode of practice may- 

 find favour from its success. Again, it may be that in disease of the lungs 

 themselves, where there is loss of structure (cavity), anhydrous chloral may be 

 inhaled in minute quantities with advantage. I name these points in order 

 to caU the attention of fellow physicians to the mode of administration I 

 have ventured to suggest. 



Connected also with anhydrous chloral is another reasonable suggestion ; 

 I mean the plan of applying the agent as a narcotic caustic to unnatural 

 growths and ulcerating fungoid surfaces. I find that by applying the fluid 

 to my arm freely there is destruction of the epidermis (scarf skin), so that 

 without any pain the epidermis peels off, almost dry, at the point where the 

 fluid has been placed ; and that when on this exposed surface some of the 

 fluid is applied, the true skin is in turn affected, so that in a day or two 

 what the ancients called an issue may be developed, the tissiies destroyed 

 coming away in the form of scales. The surgeon wiU at once see the prac- 

 tical utility of an agent possessing these properties, and he may in. some 

 instances subcutaneously inject the fluid if the outward employment of it be 

 too slow. 



It is a very curious experiment to subject freshly drawn blood to anhj'- 

 drous chloral, and to observe microscopically the changes that ensue. The 

 action of the chloral is to extract water both from the liquor sanguinis and 

 the corpuscles, and to form crystalline chloral hydrate. Into this formation 

 the shrinking corpuscles sink, ■rt'hile the fibrine remains free from precipi- 

 tation ; but if water be added, so as to dissolve and remove the hydrate that 

 has been formed, the corpuscles are to some extent restored, and the fibrino 

 coagulates and separates in the usual way. 



Metachiokal. 



Under favouring conditions anhydrous chloral is converted into an in- 

 soluble substance, to which the name of " metachloral " has been applied. 

 The change sometimes occurs spontaneously, as it has done in a specimen 

 now on the table ; but it is always effected when chloral is brought into 

 contact with sulphuric acid. Dr. Versmann has made for me some beautiful 

 specimens of metachloral by this last-named process. 



Metachloral is a white substance, easily reducible into a fine powder, but 

 insoluble in water and in alcohol. It is isomeric with chloral itself, being 

 merely different in respect to physical condition. When it is treated with 

 an alkali it yields, as chloral does, an alkaline formate and chloroform. 

 These facts led me to ask whether, in the animal body, metachloral would 

 undergo decomposition and produce specific narcotic effects : and here, again, 

 a series of results were obtained of great interest. Administered to birds in 

 the form of pilule, and to other animals either in the same form or in sus- 

 pension in glim emulsion, the metachloral, so insoluble in water, is found to 

 undergo solution in the animal secretions, and to produce the same narcotic 

 effects as the chloral hydrate, viz. narcotism, muscular prostration, and de- 

 crease of animal temperature. 



In the pigeon from ten to fifteen grains are sufficient to' take fuU effect. 

 The animal in the course of an hour becomes drowsy, and in an hour and a 

 half is in a perfect sleep, from which, nevertheless, it may be roused, to fall 

 back again into sleep with great rapidity : the sleep lasts from three to four 



