l893-] NEW-YORK MICROSCOPICAL SOCIETY. 67 



meshes could nowhere escape from the protoplasmic lump, but 

 was simply pressed from one portion, when contraction took 

 place, to another portion at rest, causing the distention of the 

 reticulum in the latter part. Should such an extremely thin, ex- 

 panded flap or pseudopodium find attachment to the slide, a 

 point of fixation is given, toward which the lump is dragged as 

 soon as the contraction ceases and rest is established. On this 

 principle is obtained an easy understanding of the form-changes 

 and locomotions of the amaba, as well as of any other living 

 protoplasmic lump. 



The question, what living matter really is, no one can answer. 

 Neither can we enter the discussion of the query. What causes its 

 contraction ? It is the innate property of the living matter in the 

 lowest plant, as well as in the highly organized human form, that 

 it contracts, thereby causing change of shape and locomotion. 

 'The second essential property is that it is able to produce its own 

 kind by taking in food and by generation. The latter feature 

 will not be considered in my address. 



When we analyze, with high powers of the microscope, the 

 structures termed " nervous," we come to the conviction that all 

 these structures are made up of living matter in an extremely 

 delicate reticular arrangement. Usually the nervous system is 

 divided into a central portion, the brain, spinal cord, and the 

 sympathetic ganglia ; a conducting portion, the nerves proper ; 

 and a terminal portion, often consisting of knob- or bud-like for- 

 mations in the peripheral organs and tissues. Undoubtedly the 

 nervous system is continuous throughout the whole animal organ- 

 ism — in other words, the brain and spinal cord are continuous 

 with all the nerves traversing the body, and these again with the 

 terminal apparatus. Long since the nervous system had been 

 compared with the telegraph, the central stations of which were 

 considered to be the brain and spinal cord, whereas the wires 

 were represented by the nerves. So close is indeed the resem- 

 blance that some physiologists have claimed that the nerve action 

 is an electric one — an hypothesis, however, never proven 



The brain and spinal cord consist of a gray and a white sub- 

 stance. The white substance is composed altogether of so-called 

 medullated nerves, and is merely a conductive apparatus. The 

 gray substance, on the contrary, is the only central apparatus of 



