The Presidents Address. By the Rev. W. E. Bollinger. 207 



diffusion of the nuclear substance, after nuclear fusion through the 

 sarcode of the united organisms, is also full of interest. 



One thing appears clear : the nucleus is the centre of all the 

 higher activities in these organisms. The germ itself appears hut 

 an undeveloped nucleus ; and when that nucleus has attained its 

 full dimensions in size, there is a pause in growth in order that its 

 internal development may be accomplished. When this is the case 

 it becomes manifest that the body-sarcode is, so to speak, a vital 

 product of the nucleus. Moreover, it is from it that the flagella 

 originally arise. In the same way it is by a complex and beautiful 

 series of deUcate activities in the nucleus that the wonderful act 

 of fission is initiated, and in all probability carried to the end. 

 So too, all the involved changes that go with fertilization and the 

 production of germs, are a series of correlated activities due, at the 

 beginning at least, wholly to the nucleus. 



"We are, as I believe, by such an investigation as this, brought 

 into close relation to the behaviour of the nucleus in the simplest 

 condition in which it is at present possible to discover it. The 

 phenomena made manifest are doubtless only the coarser and more 

 amenable activities and changes. No doubt far profounder and 

 subtiler changes are concurrently proceeding : but it is something to 

 find ourselves on the way to the observation of living changes in 

 the nucleus as they progress in the living form. 



If our lenses are improved in the next ten years, as they have 

 been in the last, in optical properties, I am convinced that remarkable 

 advances in this problem of the nucleus may be made. 



In thus coming closer to the delicate phenomena of nuclear 

 activity we of course come no nearer to the solution of what life is. 

 That is no part of the question. But to come any distance nearer 

 to a knowledge of how the most hving part of the minutest 

 organisms in nature acts in detail, has for me, and for most biologists, 

 an increasing fascination. 



I had intended appending some practical remarks on the several 

 and, so far as my experience goes, best modes of centering and 

 illuminating these high-power lenses of great aperture ; but I find 

 it needful to delay this for some future occasion. 



