312 Dre. Brunton and Cash. Connexion between [Mar. .">, 



increased excitability, greater diffusion of stimuli with diminished 

 power and definiteness of movement. Thus slight stimuli in the 

 frog produce movement more readily in the poisoned than in the 

 normal condition, bat the movement, instead of being limited to one 

 limb, vigorous and steady, is diffused over several limbs, feeble and 

 tremulous or jerking. 



In frogs, the tremors or jerking always occur on attempted move- 

 ment, and sometimes, to a slight extent, when at rest. If the done 

 be large, they are succeeded by paralysis. Absorption of the drug is 

 slow and irregular, and it may cause local rigor of the muscles. The 

 heart remains long irritable. 



Haloid radicals do not modify the action of benzene to the same 

 extent as they do that of ammonia, but they do so in somewhat the 

 same direction as the authors described in their former paper on thU 

 subject. Monochlorobenzene affects the spinal cord more than benzene, 

 causing spasm and rapid diminution of reflex. It also weakens the 

 circulation, but does not seem to affect motor nerves or muscles more 

 than benzene. " The bromo- and iodo-compounds have a more power- 

 ful paralysing action on the cerebrum than benzene and chloi 

 benzene, and the compound of iodine with benzene, like its compounc 

 with ammonia, appears to have a special tendency to paralyse motoi 

 nerves, muscles, and cerebral reflexes, and to depress the heart. Heat 

 accelerated and cold retarded the action of the substances. 



The substitution of alcohol radicals for hydrogen in bcnzem 

 appears to modify its action in much the same way as one woulc 

 expect from a general consideration of the properties of the alcohc 

 group, which, as a rule, have a sedative action on the nervoi 

 system. 



The compounds of benzene with alcohol radicals produce U 

 tremor, less hyperaesthesia, and greater lethargy than the halog 

 compounds. The circulation is little affected by them. They hai 

 little action on muscle or nerve, but act more powerfully on the nei 

 than on the muscle. Their action appears to be more fleeting ttu 

 that of the halogen compounds. Trimethylbenzene (mesitylene) 

 more active than methyl- or dimethyl-benzene. In poisoning 

 dimethylbenzene a curious increase of reflex action was observe 

 after it had almost gone, and spontaneous movement had quit 

 gone. 



Substitution of hydrogen by hydroxyl increases the tendency 

 convulsions. These are due to the action of the substances on 

 spinal cord and not on the cerebrum ; they occur independently 

 voluntary movement, except when the dose is very small, and 

 tinne almost unchanged after destruction of the cerebrum. Slight 

 tremor may occur before destruction of the cerebrum, but it is greatly 

 masked by the powerful contractions referred to. The position of the 



