4 o 



PROTOPLASM. 



in others. The germinal matter of all organisms, and of 

 the tissues and organs of each organism, exhibits precisely 

 the same characters. It lives, and grows, and forms in the 

 same way, although the conditions under which the phe- 

 nomena of life growth and formation are carried on differ 

 very much in different kinds of germinal matter. A tem- 

 perature at which one kind will live and grow actively will 

 be fatal to many other kinds. So, too, as regards pabulum, 

 substances which are appropriated by one form of ger- 

 minal matter will act as a poison to another. But the way 

 in which the germinal matter moves, divides and subdivides, 

 grows, and undergoes conversion into tissue, is the same in 

 all. Many remarkable differences in structure, properties, 

 action, and character, are associated with close similarity, 

 if not actual identity of composition. These must, there- 

 fore, be attributed not to properties of elements, physical 

 forces, chemical affinities, or other characters which we 

 can ascertain or estimate by physical examination, but to 

 a difference in vital power which is inherited, which we 

 cannot isolate, but which it would be unreasonable to 

 ignore. 



On Vital Movements. One characteristic of every kind 

 of living matter is spontaneous movement. This, unlike 

 the movement of any kind of non-living matter yet dis- 

 covered, occurs in all directions, and seems to depend upon 

 changes in the matter itself, rather than upon impulses 

 communicated to the particles from without. 



I have been able to watch the movements of small 

 amoebae, which multiplied freely without first reaching the 

 size of the ordinary individuals. I have represented the 



