16 Correlation of Microscopic FJiysiology [^jSSJli.ji^t'^s^^^^^ 
to offer an opinion. But in the paper, and more particularly in the 
discussion which followed the reading of the paper, Dr. Beale made 
requent references to various branches of physics. 
The tendency of those remarks, if I understood Dr. Beale cor- 
rectly, was to deny that any close relationship exists between 
microscopic physiology and microscopic physics. It seems to me 
desirable to state some of the leading facts that can be adduced in 
proof of such a relationship. 
Before proceeding to the parallels I wish to draw between 
microscopic physiology and microscopic physics, I must refer, briefly, 
to a point which was raised in the discussion that took place after 
Dr. Beale's paper was read, as to the instantaneous death of cells. 
Dr. Beale evidently supported this hypothesis. 
The word instantaneous is often used with respect to motions 
which take an appreciable amount of time. By the aid of the 
electric chronograph, astronomers now register the passage of time 
to hundredths of a second. 
The velocity of light is nearly 200,000 miles a second. Its 
passage across a single cell would require, then, a certain amount 
of time to complete it. Keasoning from analogy, we are forced 
to conclude that whenever a change occurs in any matter, time will 
be required for the change to be completed. 
But Dr. Beale laid the greatest stress on the motion of mucus 
as necessitating the assumption of the action of a vital force. It 
seems to me that a parallel case of motion can be found in molecular 
physics. 
When a soft iron rod is powerfully magnetized by means of a 
voltaic battery, it expands. On the connection with the battery 
being broken, it again contracts. 
This action, by a proper arrangement of the voltaic battery, can 
be easily made automatic, and would then go on until the power of 
the electricity was exhausted. During the whole time, the iron bar 
would give out a distinctly audible sound at every expansion and 
contraction. 
Faraday tried this experiment, and failed to detect the expan- 
sion. We owe the knowledge of the fact to Professor Tyndall, who 
made the discovery by using more delicate apparatus. In all pro- » 
bability Faraday would have succeeded if he had used a powerful 
microscope, furnished with a micrometer to measure the length of 
the bar. I think it is much to be regretted that physicists do not 
have more frequent recourse to the microscope. Mr. Sorby has 
made many discoveries by applying the microscope in a most inge- 
nious manner to the investigation of the structures of iron and 
steel, iron ores, and meteorites. 
Of another kind of motion, analogous to ciliary motion, my 
friend, Mr. Chandler Roberts, has kindly shown an example ; in- 
