NUCLEUS BEFORE 1860. 19 



has also ascertained that, apparently for the nourishment of 

 the component cells of a secretion of this kind, a quantity of 

 albuminous matter floats among them, by absorbing which they 

 derive materials for development after separation from the 

 walls of the gland. This albuminous matter he compares to 

 the substance which, according to Dr. Martin Barry's researches, 

 results from the solution of certain cells of a brood, and affords 

 nourishment to their survivors. It is one of other instances in 

 which cells do not derive their nourishment from the blood, but 

 from parts in their neighbourhood, which have undergone solu- 

 tion ; and it involves a principle which serves to explain many 

 processes in health and disease, some of which have been re- 

 ferred to in other parts of this work." 



From these it appears obvious that much of what was only 

 plainly understood long afterwards is anticipated, particularly 

 that the vital action resides in one constituent of the cell, 

 chiefly if not entirely, here called the nucleus, and also the in- 

 dependent life of detached and migratory particles of living 

 matter. 



The paper on " Centres of Nutrition," 1845, does not bear so 

 much on our subject, except in the unqualified assertion that 

 cells never arise except from pre-existing cells, which was after- 

 wards adopted by Remak and Virchow. It contains, probably, 

 all that is true in the theory of cell territories which Virchow 

 puts forth without sufficient acknowledgment of Goodsir's 

 priority, and does not contain the addendum of Virchow, viz., 

 the juice canals which Beale has shown to have no existence. 



The comparative unimportance of the cell wall was also shown 

 by Naegeli in 1845, and by Alexander Braun in 1851, who both, 

 in fact, maintained that it was non-essential. The credit is 

 usually, however, given to Leydig, of having, in 1857, first de- 

 cidedly declared that the cell membrane was non-essential, and 

 that the cell consisted of " a soft substance enclosing a nucleus." 

 This was confirmed in 1861 by Max Schultze, who observed 

 that very many of the most important kinds of cells were 

 destitute of membrane, and he defined the cell as " a little mass 

 of protoplasm, inside of which lies a nucleus. The nucleus, as 

 well as the protoplasm, are products by partition of similar 



22 



