DISCOVERY OF THE NUCLEUS 119 



to homologise the numerous pollen sacs either to grains of 

 pollen which, bursting, liberated fovilla, or to male flowers, or 

 to explain them in other ways, was not very successful. The 

 fact is this was a piece of morphology for which the age was 

 not ready. We must recollect that the comparative morphology 

 of the ovule (in the wide sense) was not attempted, Brown's main 

 contribution to the understanding of this structure consisted in 

 the empirical accuracy with which he elucidated the actual 

 structure he made no attempt to frame a comparative morpho- 

 logy, for the simple reason that in the condition of knowledge at 

 the time no such comparative morphology was possible or even 

 dreamed of. 



Two other remarkable discoveries now demand our attention, 

 and both are instructive as shewing the keenness with which his 

 highly trained powers of observation followed up the clues which 

 his brilliant intellect had enabled him to descry. It was while 

 engaged on a study of the Orchids and Asclepiads that he was 

 led to recognise the existence of the cell nucleus. He worked 

 almost exclusively with what we should call a dissecting micro- 

 scope. One of his instruments is preserved in the Natural 

 History Museum, and it is well to examine it and reflect on 

 how much may be discerned even with a very primitive 

 instrument if only a good brain lies behind the retina. The 

 "microscope" contains a number of simple lenses of various 

 powers, the highest about -<' F.L. It is easy with such an 

 instrument to see the nucleus in the epidermal cells when one 

 knows it is there, but to have discovered it, and at a time 

 when the technique of staining, &c., was simply non-existent, 

 was a triumph of genius. Brown, of course, could not fully 

 appreciate the great importance of his discovery, but he quite 

 realised that he was dealing with no isolated or trivial fact, and, 

 with characteristic industry and enterprise, he searched many 

 other plants to find out whether his newly recognised nucleus 

 was general or not ; he found it to be so, and we all know how 

 the discovery began at once to bear fruit. 



A second observation to which I would refer was also of wide 

 interest, and it was not made merely by chance. Brown was 

 anxious to penetrate if possible into the secrets of fertilisation. 



