466 TRANSACTIONS AND PROCEEDINGS OF THE [Sess. LX. 



am no longer able to quote any case of free nuclear 

 formation preceding cell-division." This laid the founda- 

 tion for connectini,^ the nucleus with opinions on heredity. 

 But, as above noted, the tendency of Brown's statement 

 was such as to avoid the misconceptions which delayed the 

 progress of the science, while his observation of the nucleus 

 in the cells closely connected with reproduction, seems to 

 indicate an opinion, or at least a surmise, of its importance 

 in that process. 



We may with advantage try to inquire what the verdict 

 of so careful and reticent a theoriser as Brown would be, 

 could we see the structures of hypothesis (not always 

 built upon the most scientific principles, and apt at times 

 to fall about the ears of their originators) which have 

 ari.sen in recent years on the basis of cb-servation of the 

 nucleus. I have theorised myself on the subject in last 

 year's address to you, and must not therefore be too out- 

 spoken ; but I can confidently recommend the reading of 

 Brown's three pages on the nucleus as a corrective against 

 rash speculation. 



Before leaving the consideration of this paper, I would 

 direct your attention to another footnote (p. 513), in which 

 he gives a minute account of the staminal hairs of Trade- 

 scantia ; he there describes, as observed under a lens 

 magnifying 300 to 400 times, the "circulation of very 

 minute granular matter," and how the currents pass towards 

 and from the nucleus. This is, I believe, the earliest 

 description of the circulation of protoplasm, though a much 

 more complete account of it is given by Meyer in his 

 ■' Pflanzen-Physiologie "(18 3 7). But he also dealt with more 

 minute movements which he successfully distinguished 

 from those of circulation. It was three years previous to 

 the memoir we have been discussing (1827), that Brown 

 had printed for private circulation his account of " the 

 general existence of active molecules in organic and in- 

 organic bodies ; " the.se observations of what are now called 

 " Brownian movements " were all made " with a simple 

 microscope, and indeed with one and the same lens, the 

 focal length of which is about -^^ ^^ ^^ inch." The in- 

 vestigation arose in connection with the pollen, and its 

 mode of action in fertilisation; since the ideas which then 



