86 Mr. E. Wilson's Observations on the 



a belief in the formation of the " aggregated granule " by the 

 aggregation of primitive granules, the idea which prompted 

 me to give them that name, and the formation of the aggre- 

 gated granule by the cleavage of a primitive granule. If this 

 question related merely to the formation of the " primary ag- 

 gregated granule," it would be unimportant, but it has a more 

 extended application. The outermost layer of the nucleus is 

 composed, as I have shown, of "aggregated granules," and 

 so also is that layer which alone forms the space in the nu- 

 cleolo-nucleated cells. To them the hypothesis of cleavage of 

 a simple granule would be most suitable, and this theory 

 would explain better than any other, changes which remain to 

 be described in the further growth of the epidermic cell. In 

 the second place, the relation of cell and nucleus is a question 

 on which I feel considerable doubt. The process of develop- 

 ment appears to consist in the successive production of gra- 

 nules, one layer of granules succeeding another, so that if the 

 organisable principle exist in each separate granule, the or- 

 ganisable force may be supposed to be more and more weak- 

 ened in successive formations, until the moment arrives when 

 it ceases entirely. Is that which I have described as a nu- 

 cleolo-nucleated cell really a cell or still a nucleus? The only 

 solution of the question that occurs to me is, determining the 

 presence of a cell-membrane, in which I have not satisfactorily 

 succeeded. 



Admitting the nucleolo-nucleated bodies now described to 

 be cells in their earliest state of formation, their size is smooth 

 to 2joo tn °f an nicn m tne l° n & diameter, and that of their nu- 

 cleus from 77(j\joth to ^jyo 1 ' 1 of an inch. In the stratum im- 

 mediately above the deepest layer, I find cells measuring 

 -^--th of an inch with nuclei of T joyth. Above these, cells 

 measuring T a\jo tn > with nuclei varying from ¥IJ ^th to ^^th, 

 and above the latter cells measuring y^^th, with nuclei of 

 _ T i__th. In following the layers of the epidermis upwards to 

 the surface, cells may be observed possessing every interme- 

 diate degree of size between the last-mentioned cell, namely 



1 th and ^Anth, which is the measurement of the scales 



1.5 00 , l)UO ' . 



which constitute the uppermost stratum of the epidermis. It 

 must not be supposed, however, that the growth of the epi- 

 dermic cells reaches its maximum only at the surface : I have 

 found cells of that magnitude in the deeper strata; and there 

 is every indication of the growth of these cells being com- 

 pleted in the stratum immediately above the mosaic-like 

 layer. 



Young cells are remarkable for the large size of the nucleus 

 as compared with the entire bulk of the cell; and it is quite 



