ANIMAL AND VEGETABLE 159 



healthy begonia and obtained a steady deflection of 

 135 mm. upon the galvanometer scale. The injection of 

 two minims of tincture of nux vomica into the stem 

 reduced that deflection to zero in one hour. In six hours 

 the stem fell, the leaves separated at the junction of stalk 

 with stem, and in a week the plant was rotten. 



The point laboured by at least some investigators seems 

 to be that although a nerve or nerves may be paralysed or 

 deprived of conductivity by certain poisons, the excitability 

 of muscle may not be so affected, and therefore the muscle 

 is independent of nerve. 



Expose that theory to the cold light of reason. In the 

 first place, the poison the destructive agent must pene- 

 trate not only the nerve but invade the whole of the sarco- 

 meres as is possibly the case in gas gangrene if the latter 

 are to be equally affected ; secondly, if the resistance of the 

 clear lines of muscular fibre is correspondingly increased, 

 so, conceivably, would be the resistance of Krause's mem- 

 branes, and therefore contraction might still be possible, 

 though in diminished degree. If it is a matter, merely, of 

 poisoning, or, in other words, " sealing, " the motor nerve, 

 the excitability should, according to the theory I have 

 advanced, endure for a longer period than if the nerve had 

 not been poisoned or insulated. 



Under the microscope single muscular fibrillae exhibit 

 the same phenomena as an entire muscle, in that they 

 contract and become thicker. Though there is difficulty 

 in observing the changes that occur in the individual 

 parts of a muscular fibre during the act of contraction, it 

 appears to be certain that the muscular elements become 

 shorter and broader during contraction ; that is to say, the 

 transverse striae approach nearer to each other in the 

 manner I have indicated. 



Too much importance should not, for reasons I have 

 given, be attached to experiments with dead muscle unless 



