ON THE ACTION OF THE METHYL AND ALLIED SERIES. 163 



crystalline forms whicli have been described, since the time of Dr. Pdchard 

 Mead, as occurring in the blood after infection by the poison of the viper. 

 One other peculiarity in the action of the ethylates on blood is worthy of 

 notice : while they seem to attack and dissolve the red corpuscles vigorously, 

 they act with comparative slowness on tlio white corj)usclos, so that wo may 

 often see a white corpuscle iloating uninjured in a sea of red colouring- 

 fluid previous to crystallization, and even adhering to the crystalline points 

 after crystallization. 



The ethylates jwssess also powerful antiseptic properties, so that even 

 nervous matter, which of all animal substance is most jjrone to decomposition, 

 can be long kept in good preservation in the presence of them. I have by 

 me, in bottles, specimens of the brain of sheep which illustrate this point. 

 Specimen 1 is inclosed in common air, and is a decomposed fluid mass. 

 Specimen 2 is inclosed in the same volume of air, with twenty grains of 

 absolute alcohol : this specimen is decomiioscd. Specimen 3 is inclosed in 

 the same volume of air, with twenty grains of the ethylate of sodium ; it 

 remains firm, of perfectly natural colour, and free of decomposition. The 

 specimens have been now under observation for fifteen weeks. 



Sulphur Alcohol, Mevcaptan. — The sulph-hydrate of ethyl, sulphur alcohol, 

 or, as it was originally called by its discoverer, Zeise, " mercaptan,"' is made 

 by saturating an alcoholic solution of potassa with sulphuretted hydrogen, 

 and then treating the solution with iodide of ethyl. In its jjure state it is a 

 whitish fluid, and of so ofli'ensive and penetrating an odour that it cannot, 

 until it is diluted with common alcohol or ether, in both of which it is freely 

 soluble, be comfortably employed in experiment. It is insoluble in water. 

 Its specific gravity is -832 at 70° F. ; its boiling-point is 135° F., and its 

 vapour-density, by side of hydrogen, is 31. It is nearly insoluble in water, 

 but imparts to water its peculiar odour, and can be distributed freely through 

 it if combined with alcohol. 



In order to experiment with mercaptan, it is necessary to dilute it either 

 with absolute ether or alcohol ; a solution containing one per cent, is sufli- 

 ciently active. 



When blood is acted upon by mercaptan no change of colour is produced, 

 neither is the action of peroxide hydrogen on blood influenced by its pre- 

 sence. The corpuscles are made slirunken by it, but are not destroyed, their 

 form changing into ovoid, with the same production of truncated cor- 

 puscles which I described in my last Eepoit as belonging to the action of 

 ordinary alcohol. 



When mercaptan is cautiously inhaled the physiological eff'ects are most 

 peculiar. I found, by a direct experiment made on myself, that the vapour is 

 nowise irritating, but that systemic eftects are very speedily pronounced. There 

 is desire for sleep, and a strange unhappy dreamy sensation, as if from some 

 actual or impending trouble. This is succeeded by an easy but extreme 

 sensation of muscular fatigue ; the limbs feel too heavy to be lifted, and rest 

 is absolutely demanded. There is at the same time no anaesthesia and no 

 sign of intoxication. The pulse is rendered feeble and slow, and remains in 

 that condition for one or two hours. In time all the effects pass off", and no 

 unpleasant symptom remains. Active motion in the air very quickly gives 

 entire liberation from the efl^ects of the agent. 



The same effects are produced on the inferior animals. Frogs exposed to 

 the vapour pass slowly into sleep, and if the inhalation be sustained, there 

 is complete arrest of the acts of respiration and circulation, followed by 

 arrest of movements of the limbs. In this condition the animals lie to all. 



m2 



