LIFE. 



and will probably be ere long generally used Biology, 

 or the science of life. 



Emily. I have always thought that I had a suffi- 

 ciently correct idea of life, but after the rigid precision 

 with which you have defined your terms, I am afraid 

 that my notions will prove rather indefinite. The terms. 

 vital principle, living principle, &c. have led me to con- 

 sider life as something altogether distinct, and superad- 

 ded to the body ; in the same manner as the mind is 

 considered to be a principle distinct from, and independ- 

 ent in its existence of the brain. 



Dr. B. Your notions are erroneous, but it is not al- 

 together your fault, since they have prevailed among 

 medical men themselves, who have strangely mistaken 

 an abstract term, for a self-existent and governing prin- 

 ciple This mistake, which arose, no doubt, from a 

 want of precision in medical language, is for this reason 

 unpardonable now. By some of the best physiologists 

 of the present day, the term life is used to express the 

 general aggregate or combination of those properties 

 which are peculiar to living beings, and which are also 

 called living, or vital properties. The only correct defi- 

 nition of life, therefore, would be the enumeration of 

 these properties, and we can obtain exact and compre- 

 hensive notions of it, only by considering what these 

 properties actually are. 



Emily. Do, Dr. B., explain them, for I am impa- 

 tient to know what these curious properties are, that are 

 so different from impenetrability, divisibility, attraction, 

 &c. which are common to all matter. 



Dr. B. In the first place then, every organized body 

 is composed of both solids and fluids which are continu- 

 ally in motion continually acting on each other. This 

 is necessary to the very conception of a living being. 



Emily. But you forget that crystals contain a cer- 

 tain portion of water, which is essential to their existence 

 as crystals. 



Dr. B. But it is water in a solid state there is no 



