5D5§ Tue Microscope. 
with the reticulum of the nucleus, without ever being distinetly 
traceable into its centre, respectively, the nucleoli. Some of the 
threads, 7. e. the most delicate ones, run into the basis-substance 
and here inosculate with its delicate reticulum whieh, in this 
situation, often is found a trifle coarser than in the rest of the 
basis-substance. The beaded or rosary-like structure of the 
thread is retained to the last, viz., to the point of insertion into 
the reticulum. 
Thus far I have contented myself with the deseription of facts 
plain and pure but not easily recognizable by eyes insufficiently 
trained in the art of seeing with the microscope, ladmit. I now 
proceed to reasoning, such as must force itself upon the mind of 
every unbiased observer. The facts laid down are not amenable 
to criticism ; my reasonings and conclusions undoubtedly are. 
“ The tissues are made up of cells and intercellular substance.” 
Such is the teaching of the cell theory. What is a cell? Nobody 
knows. A lump of protoplasm, the most advanced histologists 
claim, and representing an isolated individual endowed with 
properties of life. 
If we watch the cornea of a frog, excised and kept alive by 
the addition of some aqueous humor of the eye, or serum of the 
blood, we may look, even with high powers of the microscope, 
through its whole thickness. At first this appears homogeneous, 
almost structureless, with faint cloudy shadings. ~- By and by, 
grayish, branching formations will emerge, known as the proto- 
plasmic bodies of the cornea or “ cornea-cells.” It has long since 
been proved that these bodies are alive in the. living cornea, 
amceboid, viz., may change their shapes under the influence of 
a weak Faradiec current. The longer we keep the cornea alive 
the more of its protoplasmic bodies become conspicuous, all 
being branching and inter-connected. W. His, as early as 1856, 
described the cornea corpuscles of a child as branching and inter- 
connecting bodies, of such a breadth and profusion that the in- 
tervening basis substance would occupy less space than the 
cornea corpuscles themselves. He, therefore, was the first accur- 
ate observer of the cornea corpuscles, and his description and 
figures certainly agree with my own drawing of the cat’s cornea, 
with the exception that he used a much lower power of the 
microscope than I. 
Where are the cells? Where are the individuals? The 
