WITH THE MICROSCOPE. 169 



sufficiently explained and accounted for if they are attributed to this 

 mystical property of contractility. They do not attempt to define 

 what they mean by the word, nor do they show in what this supposed 

 property resembles or differs from other properties of matter. They 

 do not state whether it is peculiar to the living state or is manifested 

 after life has ceased. 



Many facts have convinced me that there is an absolute difference 

 between living, and non-living matter, and I maintain that the asser- 

 tion that the non-living passes by gradations into the living is not 

 justified in the present state of scientific knowledge. 



Some of the most remarkable phenomena which distinguish living 

 from non-living matter may now be observed under the microscope with 

 the aid 'of the highest powers. There is no department of natural 

 knowledge in which a greater advance is to be noticed than in this, 

 and the facts which have been recently discovered enable us to draw 

 a sharp and well-defined line between living things and the various 

 forms of non-living matter, be it of simple or complex composition. 

 If as investigation still further advances the facts already known are 

 confirmed, and the conclusions arrived at from recent researches, 

 supported by new observations and experiments the operation of 

 some agency, force, or power in living matter, distinct from every 

 kind of physical force operating in non-living matter must be ad- 

 mitted, and the views at this time most popular, will have to be 

 modified in most important particulars. 



If the student studies this question carefully, he will, I think, 

 find that confusion has arisen from the attempt to account for several 

 essentially different kinds of movements by one property, con- 

 tractility. Thus any tissue which alternately becomes shortened or 

 lengthened, gaining in one diameter what it loses in another, is said 

 to be contractile, while on the other hand, that which moves in 

 every conceivable direction is said to do so by virtue of the same 

 property. It is not, however, very easy to see how two such dif- 

 ferent movements, as repeated acts of contraction and relaxation 

 within a definite space, and the actual movement of a mass from 

 place to place, can depend upon one and the same property. In 

 fact, it has yet to be shown that the many different movements 

 commonly known to occur in living things are really all of the same 

 nature. I would arrange the movements occurring in living beings 

 as follows : 



i. PRIMARY OR VITAL MOVEMENTS affecting matter in the 

 living state only, and occurring in every direction, as seen in the 

 amaeba, white blood corpuscle, and in germinal or living matter 

 generally. 



