ON NEliVOUS SYSTEM AND MUSCLES. 477 



Action on the Nervous S//stem. — In fropjs nitro-glycerine pro- 

 duces, as we have already mentioned, languor, tetanus, and 

 finally paralysis. In cats there is paralysis without any tetanus, 

 although there may be movements of a convulsive nature — 

 such as vomiting, spasmodic respirations like hiccough, and 

 jiiuscular twitches — when the poison is injected into the abdo- 

 minal cavity. In another experiment w^e found that after the 

 injection of 1 cubic centimetre of a 10 per cent, solution 

 directly into the jugular vein of a cat, tetanic convulsions 

 occurred. 



In order to ascertain whether the tetanus in the frog is due 

 to the action of the nitro-glycerine on the spinal cord, or on the 

 nervous centres within the encephalon, the s]3inal cord was cut 

 across about the middle before the poison was given. The 

 upper part of the animal immediately became very restless, 

 and the arms were stretched out at right angles to the body 

 with the toes outspread. There v/as no alteration in the hinder 

 part of the body and legs. The nitro-glycerine, therefore, does 

 not cause tetanus by its direct action on the spinal cord, as other- 

 wise spasms would have been observed in the hind legs. This 

 result was confirmed by another experiment. A frog was 

 decapitated, and after the spinal cord had recovered from the 

 shock, and reflex movements were again observed in the limbs, 

 nitro-glycerine was injected under the skin. No spasm what- 

 ever was observed. Other experiments led us to believe that 

 the tetanus is not due to any action on the cerebral lobes, but 

 probably to the effect of the poison on the optic lobes ; but we 

 are not yet in a position to decide this with certainty. 



Action on Muscle. — In order to ascertain this, two gastro- 

 €nemii of a frog were immersed in two glasses, each containing 

 10 cubic centimetres of a '75 per cent, solution of common salt. 

 To the one glass about two drops of the solution of nitro- 

 glycerine were added. After three hours the muscle which had 

 been lying in the pure solution of salt contracted readily on the 

 application of an induced current, while the one which had been 

 lying in the salt solution with nitro-glycerine was in*a state of 

 rigor mortis. Nitro-glycerine is therefore a muscle poison, and 

 in this particular its action agrees with that of nitrites, all of 



