GOODSIR. 17 



cell is impossible, and no chemical test could be applied. In 

 the first publication of this memoir, in the " Transactions of the 

 Royal Society of Edinburgh," he follows mainly Schwann, 

 thinking that the nucleus is the reproductive organ of the cell, 

 and has nothing to do with the formation of the secretion. He 

 adds " I believe that the cell wall itself is the structure by 

 the organic action of which each cell becomes distended with 

 its peculiar secretion at the expense of the ordinary nutritive 

 medium which surrounds it" (p. 417). But in the republica- 

 tion of the article, in 1845, he says " The ultimate secreting 

 structure is the primitive cell endowed with a peculiar organic 

 agency, according to the secretion it is destined to produce. I 

 shall henceforward name it the primary secreting cell. It con- 

 sists, like other primitive cells, of three parts the nucleus, the 

 cell wall, and the cavity. . . . The secretion within a primitive 

 cell is always situated between the nucleus and the cell wall, 

 and would appear to be a product of the nucleus n (p. 417). 



He then states at p. 426 : " Since the publication of 

 my paper on the secreting structures, in the ' Transactions 

 of the Royal Society of Edinburgh,' in 1842, I have satis- 

 fied myself that I was in error in attributing to the cell 

 wall the important function of separating and prepar- 

 ing the secretion contained in the cell cavity. The nucleus 

 is the part which effects this. The secretion contained 

 in the cavity of the cell appears to be the product of the solu- 

 tion of successive developments of the nucleus, which in some 

 instances contains in its component vesicles the peculiar secre- 

 tion, as in the bile cells of certain mollusca, and in others be- 

 comes developed into the secretion itself, as in seminal cells. 

 In every instance the nucleus is directed towards the source of 

 nutritive matter, the cell wall is opposed to the cavity into 

 which the secretion is cast. This accords with that most im- 

 portant observation of Dr. Martin Barry, on the function of 

 the nucleus in cellular development." 



Having, as above, described the nucleus as the generative, or 

 reproductive organ of the cell, he now shows that repro- 

 duction and secretion are in reality varieties of the same pro- 

 cess. " There are, in fact," he says, " three orders of secretions 



2 



