1881.] Poisons of certain Indian Venomous Snakes. 339 



completely destroyed by poison, as to render the animal dependent on 

 artificial respiration for life. 



In this direction another point mnst be taken into acconnt. It has 

 already been stated that one of the most characteristic features of 

 cobra poisoning in the human subject is paralysis of the legs. The 

 patient is unable to walk or to stand, though his arms have not as yet 

 experienced any loss of power. Now, it would be difficult to suppose 

 that this was due to the terminations of the motor nerves of the legs 

 becoming paralysed, while those of the arms remain unaffected. It 

 is much more probable that the spinal cord is becoming paralysed, one 

 of the first effects of which would be that it would lose the power of 

 maintaining the tone and necessary contraction in the many complex 

 groups of muscles on which the upright posture is dependent. But 

 in cobra poisoning in dogs paralysis of the hind limbs without the 

 fore is rarely seen. In the vast majority of cases power is lost 

 simultaneously in all four members. In those few cases in which it 

 has been noticed that the hind legs have suffered first, the animal has 

 been bitten on the hind leg, which would always cause a certain 

 amount of lameness and difficulty in walking with the hind quarters, 

 due to the local effect of the poison. But even with this source of 

 fallacy it holds good that in men suffering from cobra poisoning 

 paraplegia is a most constant symptom, whereas it is very exceptional 

 in dogs. The reason of this great dissimilarity is to be found in the 

 different functions of the inferior portion of the spinal cord in the 

 two cases. In man the lower portion* of the cord is, to a great extent, 

 a distinct nervous centre. The ganglia there not only are the centres 

 on which the lower limbs rely for their nerve power to maintain the 

 upright posture, but the sensation of contact with the ground of one 

 foot in walking is translated in these lower centres into a motor 

 stimulus to excite movement in the other leg, and paralysis affecting 

 these centres would at once destroy the process. But in dogs the 

 mechanism is very different. They move the foreleg of one side with 

 the hindleg of the other. It is necessary, then, that the centres 

 governing the movements in these limbs should be coupled — so to 

 speak — together. The stimulus that moves the foreleg of one side 

 has to excite simultaneous movement in the hind leg of the other. 

 Therefore the posterior extremity of the cord has in the dog merely 

 to transmit the motor impulse from the forepart, whereas in man it 

 has to translate sensations into stimuli to excite movement, and this 

 in man is the first faculty destroyed by cobra poison. It is, therefore, 

 probable that the earliest injury inflicted on the nervous system by 

 cobra poison is a paralysis of the centres in the lower part of the 

 spinal cord. 



The next symptoms of cobra poisoning are very characteristic. The 

 patient loses power of speech, of swallowing, of moving the lips, the 



