BIOLOGICAL APPARATUS. 



INSTRUMENTAL appliances^ of a simple character have been 

 used by students of the Biological Sciences from the earliest 

 times ; but the employment of delicate apparatus, and especially 

 of instruments of precision, for the quantitative admeasurement of 

 the forces exerted by living matter, is of comparatively recent 

 date. In fact, the conception of the problems to the investigation 

 of which such apparatus is applicable was impossible until the 

 physical and chemical sciences had reached a high degree of 

 development, and were ready to furnish not only the principles 

 on which the methods of the physiological experimentalist are 

 based, but the instruments with which such inquiries must be 

 conducted. 



Of the two principal divisions of biology namely, morphology 

 and physiology it is obvious that the former, as a science based 

 upon the observation of the forms and structure of animals and 

 plants, is, by its nature, less dependent upon other branches of 

 knowledge than physiology, which, in the long run, is the appli- 

 cation of the laws of physics and chemistry to the explanation of 

 the phenomena of life. 



Thus, systematic zoology and botany, so far as they could be 

 founded upon the observation of external forms and rough inspec- 

 tion of internal structure ; and even anatomy, so far as it can be 

 carried by unassisted vision, made very considerable progress 

 without other aid than that derived from such ancient and simple 

 instruments as knives, scissors, saws, forceps, pins, and hooks, 



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