October 6, 1905.] 



SCIENCE. 



419 



whether a ner.ve ends in a sympathetic 

 ganglion or passes through it, as is the 

 case, for example, with the trigeminus 

 fibers through the ciliary ganglion. 



The study of the action of a wholly dif- 

 ferent type of poison, namely tetanus 

 toxin, has also furnished a series of impor- 

 tant facts relating to the field of neuro- 

 physiology. If one injects into an extrem- 

 ity of a warm-blooded animal a sterile 

 toxin derived from tetanus bacilli, there 

 occurs, as is well known, a local tetanus, 

 that is to say, the inoculated limb enters 

 into tonic extension and shows, especially 

 in the later stages of the poisoning, an 

 increased reflex irritability, while all the 

 remaining parts of the body continue to 

 retain their normal position and normal 

 reflex excitability. Now, it was possible to 

 shoAv that this remarkable phenomenon 

 arose through the circumstance that the 

 poison was absorbed by the adjacent motor 

 nerve-ends and carried upward in the axis 

 cylinder to corresponding centers of the 

 spinal cord. The blood and lymph chan- 

 nels are wholly unconcerned in this trans- 

 portation of the poison, and there conse- 

 quently remains only the possibility that 

 there is constantly flowing through the axis 

 cylinder of the motor nerves a centripetal 

 protoplasmic stream, reaching as far as the 

 ganglia of the neurones. This was a pre- 

 viously unknown fact which must be of 

 significance for the nutrition of the nerves 

 and also for the trophic disturbances of the 

 central ganglia which develop after section 

 of the peripheral nerves. I .have also 

 found that such a centripetal flow of diph- 

 theria toxin occurs in the nerves and the 

 same thing seems to be true of certain 

 metals which, like lead, give rise to chronic 

 neuritic palsies. Perhaps a stream of this 

 kind passes also along the sensory nerves, 

 but in any case its course is arrested by the 

 spinal ganglia, so that the tetanus poison is 

 here held fast and is unable to reach the 



sensory apparatus of the spinal cord. If, 

 on the other hand, one injects the posterior 

 nerve-roots between the root ganglion and 

 cord, there occurs an irritation of the sen- 

 sory pain-exciting apparatus in the spinal 

 cord and, indeed, without simultaneous ir- 

 ritation of motor or reflex structures. 

 There thus arises the pure so-called tetanus 

 dolorosus, which is characterized by the 

 periodical recurrence of extremely painful 

 seizures, excited apparently through the 

 summation of minimal and, ordinarily, 

 wholly inactive stimuli. It makes no dif- 

 ference, as regards the development of the 

 phenomenon, whether the spinal ganglion 

 has or has not been removed — a fact which 

 was shown by Fletcher. In this manner 

 has arisen the proof of the existence of 

 wholly special pain-subserving structures 

 in the central mechanism of the spinal cord 

 (the existence of which was long denied by 

 French physiologists-) — structures distinct 

 from those subserving tactile and motor 

 functions. 



Finally these investigations have brought 

 to light another remarkable fact. In the 

 ordinary poisoning through tetanus toxin 

 the muscles are the seat of two distinctly 

 different kinds of phenomena. In the first 

 place, the involved muscles become short- 

 ened without undergoing contraction in the 

 physiological sense. This condition may 

 exist alone. In the resting state they show 

 neither the electrical phenomena nor the 

 heat production nor the muscle tone that 

 characterizes a state of activity. They 

 shorten only slowly and the affected ex- 

 tremity thus becomes stiff and gradually 

 immobilized. If the muscles have not un- 

 dergone maximal shortening, they are still 

 capable of voluntary or reflex contraction, 

 as in the case of normal muscles. It is only 

 later that we see the well-known strychnine- 

 like reflex tetanus in which the muscles are 

 implicated in rapidly recurring, increas- 

 ingly accentuated contractions. Since it is 



