400 



Dr. H. W. Pomfret. Organic Oximides : [May 4, 



seen when dilute solutions are used ; but the dilution must be in- 

 creased with the atomic weight of the aldehyde. 



There is a primary shortening of the latent period which also 

 varies as the primary stimulation. This same action is also reflected 

 in the muscle curves, where the abrupt ascent and increased height, 

 whilst always to be seen as initiatory effects, are found to become 

 more transient. At the same time the descending arm of the curve 

 always shows the rigidity of contracture, and that in increasing- 

 degree. 



As the group of aldehydes is ascended, muscle-nerve preparations 

 show a gradually increasing loss of irritability in the nervous path, 

 both absolutely and also slightly in comparison with a similar loss of 

 irritability in the muscle itself. 



A primary slight exaltation of irritability in the nervous path also 

 becomes a little more evident, and, since the nerve trunks have shown 

 no such action, the nerve endings must be the seat of such primary 

 stimulation. 



In their action on the spinal cord these fatty aldehydes produce a 

 primary increase of irritability followed by a secondary depression. 

 The intensity of this primary stimulation of the spinal cord seems 

 scarcely to vary in the case of the lower three members, that is to 

 say, ethyl-, propyl-, and isobutyl-aldehyde, whereas the potency of 

 their secondary depressant action intensifies with their increasing 

 weight. CEnanthol causes a more marked primary stimulation of 

 the cord than would inferentially be expected, and may cause reflex 

 convulsions in the frog. 



Ethyl-, propyl-, and isobutyl-aldehyde all constrict the vessels of 

 the excised sheep kidney. This action varies inversely as the atomic 

 weight ; thus, isobutylaldehyde constricts the vessels less than propyl- 

 aldehyde and the latter less than the ethyl compound. CEnanthol 

 first constricts and then dilates the same vessels. In the tortoise 

 ethylaldehyde and propylaldehyde are again vaso-constrictors. The 

 effect of pithing the cord in the tortoise has shown that both ethyl - 

 and propyl-aldehyde have a local constrictory influence on the vessel 

 walls, and it would appear that this action is reinforced during the 

 period of exalted sensibility of the cord by a like influence exerted 

 through the spinal centres. As the cord becomes depressed this 

 central constricting influence is abolished, or even replaced by an 

 influence antagonistic to the local constrictory action. 



Isobutylaldehyde dilates the tortoise's vessels slightly, and the 

 action increases somewhat as the circulation is continued. This 

 vaso- dilating action of isobutylaldehyde is again exerted locally on 

 the walls of the vessels, and is at first either uninfluenced by, or is 

 slightly antagonised by, the spinal cord ; later, a vaso-dilating in- 

 fluence is also exerted through the spinal centres. 



