1903.] Researches on Tetanus. 27 



or but slight, symptoms, is often sufficient to produce death if injected 

 into a motor nerve. 



5. Even when the blood contains a large quantity of anti-toxine it is 

 still possible to produce tetanus by injecting toxine into a motor nerve, 

 although, under similar circumstances, subcutaneous or intravenous 

 injections calls forth no symptoms whatever. 



II. The Period of Incubation. 



If the path of the toxine is centripetal along the motor nerve, we 

 should expect that injection direct into the substance of the nerve 

 trunk would shorten the period of incubation. 



If it were possible to introduce the toxine at once into the neigh- 

 bourhood of the susceptible centres of the spinal nervous system, this 

 shortening ought to be still more marked. 



Both these anticipations are strikingly confirmed by our experiments. 

 We are, therefore, of opinion that the greater part of the period of incu- 

 bation is the expression of the time occupied in the conveyance of the 

 toxine from the periphery along the motor nerves to the susceptible 

 centres. 



The results of our injections of toxine into the spinal cord are 

 furthermore of great interest in that they prove that not only the 

 exaggeration of the reflexes, but also the so characteristic tetanic rigidity 

 of the muscles is due to the action of the toxine on the nervous centres 

 to the entire exclusion of the periphery. 



III. Tetanus Dolorosus. 



In all our experiments with injection of tetanus toxine into the 

 substance of the spinal cord we observed, as the first symptom of 

 intoxication, an extremely remarkable sensory disturbance which 

 remained strictly localised, even when the muscular rigidity and the 

 exaggeration of the reflexes were becoming general. In several cases, 

 indeed, this sensory disturbance was so great as to lead to death, 

 apparently from exhaustion, before the ordinary symptoms of tetanus 

 were clearly developed. 



Briefly, this symptom consisted in extreme hyperczsthesia of some part 

 of the periphery corresponding to the spinal centre into which the 

 injection had been made. This over-irritability of the pain-reflex 

 apparatus is certainly due to the action of the toxine and is quite 

 apart from the ordinary tactile-motor reflex tetanus. It never occurs 

 after simple subcutaneous or intravenous administration of the toxine, 

 nor after injection into a nerve trunk. On the other hand, if the 

 toxine be introduced direct into a posterior root the result is pure tetanus 

 dolorosus, thus indicating that the spinal ganglion forms an insuperable 

 obstacle to the transport of the toxine. 



