APPARATUS FOR PHYSIOLOGICAL 

 INVESTIGATION. 



BY DR. BURDON-SANDERSON. 



WHENEVER it happens that I have to discuss the progress 

 of discovery in physiological science during the present 

 century, the fact forces itself on my mind, that the year 

 1850 marked the commencement of a new era an era 

 which can be compared in importance with none excepting 

 that of Harvey. The two epochs differed, however, from each 

 other in one remarkable respect : that, whereas Harvey's 

 achievement was a consummation, the other was merely a 

 commencement. Harvey, by his crowning discovery, gave 

 meaning and completeness to the discoveries of his pre- 

 decessors, but the process which began from the middle 

 year of the present century has been a gradual one, of 

 which the rapidity and extent are still increasing. It 

 cannot be regarded as the work of any one individual, or 

 as the result of any one discovery. If it be asked how 

 this is to be accounted for, the answer must be, that it 

 arose out of the still more rapid progress already made in 

 those more exact branches of natural science included in 

 the terms physics and chemistry, on which physiology is 

 based, and of the application of their methods to the 

 investigation of the phenomena of living beings. I will 

 give you three instances of this : the application of the 

 microscope to the investigation of the structure of plants 



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