440 FEAGMENTS OF SCIENCE. 



its physical correlative in that organ; and nothing can 

 be more certain than that every physical change, whe- 

 ther molecular or mechanical, requires time for its 

 accomplishment. So that, besides the interval of trans- 

 mission, a still further time is necessary for the brain 

 to put itself in order for its molecules to take up the 

 motions or positions necessary to the completion of 

 consciousness. Helmholtz considers that one-tenth of 

 a second is demanded for this purpose. Thus, in the 

 case of the whale above supposed, we have first half a 

 second consumed in the transmission of the intelligence 

 through the sensor nerves to the head, one-tenth of a 

 second consumed by the brain in completing the arrange- 

 ments necessary to consciousness, and, if the velocity of 

 transmission through the motor be the same as that 

 through the sensor nerves, half a second in sending a 

 command to the tail to defend itself. Thus one second 

 and a tenth would elapse before an impression made 

 upon its caudal nerves could be responded to by a whale 

 forty feet long. 



Now, it is quite conceivable that an injury might 

 be inflicted so rapidly that within the time required by 

 the brain to complete the arrangements necessary to 

 consciousness, its power of arrangement might be des- 

 troyed. In such a case, though the injury might be of 

 a nature to cause death, this would occur without pain, 

 Death in this case would be simply the sudden negation 

 of life, without any intervention of consciousness what- 

 ever. 



The time required for a rifle-bullet to pass clean 

 through a man's head may be roughly estimated at a 

 thousandth of a second. Here, therefore, we should 

 have no room for sensation, and death would be pain- 

 less. But there are other actions which far transcend 

 in rapidity that of the rifle-bullet. A flash of light- 



