October 11, 1895.] 



SCIENCE. 



designates the uncontrollable, fruitless, nervous 

 activity superinduced by over-fatigue, and which 

 is so exhaustive to the nervous centers. He 

 shows, furthermore, by his experiments on car- 

 rier pigeons, that excessive muscular fatigue 

 produces ansemia of the brain. A slight modifi- 

 cation in cerebral circulation is sufficient to im- 

 pair the intellectual faculties and may even de- 

 termine a swoon. In experiments made upon a 

 subject named Bertino, the author produced 

 syncope and convulsions by a compression of 

 the carotid arteries — an opening of some half 

 inch in the frontal region of his subject, 

 enabling him to register the pulsations of the 

 brain meanwhile. 



Every one has heard of curare, first intro- 

 duced into Europe in 1595. It is a dark-brown, 

 solid substance contained in little earthen pots, 

 as prepared by the Indians of Sovtth America, 

 by whom it is used principally to poison their 

 arrowheads for war and the chase. The active 

 principle in curare is its curarine, a ternary 

 substance consisting of azote, hydrogen and 

 carbon. This substance has two remarkable 

 qualities : Contrary to what is usually the 

 case with vegetable poisons, it may be ab- 

 sorbed internally with impunity, and in fairly 

 large doses (by mammals, at least), whereas 

 in the forfia of hypodermic injections it becomes 

 a violent poison. On the other hand, it does 

 not affect the nervous centers — the mental 

 powers, the sensitive nerves and the muscles, 

 while paralyzing the motor nerve. It doubtless 

 especially affects the terminal plate where the 

 motor nerve unites with the muscle. It kills 

 hy arresting the heart's action. 



Professor Wedensky, of the St. Petersburg 

 University, has lately reproduced the .paralyz- 

 ing effect of curare by a very different process. 

 With the electric apparatus of Dubois Raymond 

 he excites the motor nerve by frequent and 

 violent currents. Under the influence of this 

 irritating treatment, the muscle, instead of con- 

 tracting, relaxes almost completely, and its con- 

 dition becomes analogous to that produced by 

 the mysterious influence of the curare. As the 

 intensity and frequency of the'se excitations are 

 diminished, the muscle tends to resume its con- 

 tractile power and to return to its normal 

 state. 



These experiments are of the greatest interest. 

 They show the fatal consequences attending fre- 

 quent and intense nervous effort ; they jsermit 

 us at the same time to calculate the danger 

 of paralysis and to anticipate it. These new 

 processes enable us to distinguish the normal 

 muscle from the enervated muscle — that is to 

 say, the muscle deprived of the influence of the 

 spinal marrow and the nervous fibres — after 

 long and intense irritation, whether caused by 

 over-taxation of the brain or of the muscles. 



Professor Wedensky calls attention to the 

 fact that the enervated muscle in presence of 

 the electric batterjr acts in a much simpler 

 manner than the normal muscle when the 

 excitations traverse the tissues in their en- 

 tire length. The normal muscle, subjected to 

 currents of gradually increasing intensity, will 

 contract but slightly at first, then more, and 

 then less again; whereas, the enervated muscle 

 will increase its contractions with the intensi- 

 fied current, relaxing as the intensity dimin- 

 ishes. Furthermore, if a second current be 

 added to the first, it will have no effect on the 

 normal muscle, while for the enervated muscle 

 the second current reinforces the first. 



A stethscopic auscultation of the muscles after 

 fi'equent irritations will, in case of enervation, 

 reveal sounds whose rhythm corresponds almost 

 exactly with that of the induced current ; the 

 vibrations of the normal muscle, on the con- 

 trary, will be foiind to maintain their own in- 

 dependent rhythm. 



Finally, it must be remarked that the normal 

 muscle is much more excitable under the in- 

 fluence of an ascending current than a descend- 

 ing one. The contrary is the case for the en- 

 ervated muscle, and even for the muscle that is 

 simply fatigued. 



From these facts results an important practi- 

 cal application, an exact method for the exami- 

 nation of cases of fatigue and paralysis. For in- 

 stance, let the subject under examination clasp 

 in his right hand the negative pole while the 

 positive pole rests on his" right foot; then ascer- 

 tain the degree of intensity required to produce 

 the least possible contraction of the muscles 

 traversed by the current ; whereupon reverse 

 the order of the electrodes, placing the positive 

 above and the negative below, thus subjecting 



