1896-97-] Plant Origins. 289 



lists of the plants and animals of our district and doing nothing 

 more. We want to reason from our individuals — how they work, 

 and how this living cosmos works. The question which con- 

 tinually presents itself to all who occupy themselves with the 

 study of living things is, How has the individual organism — 

 this insect, or this oak, or this man — become what it is ? 

 When a variety suits its environment, it becomes lasting, and 

 we call it a species ; and as time goes on and a species pre- 

 serves more and more the residual effects of previous environ- 

 ment, we call that heredity. If we study a group, even an 

 order or a genus, we get to see the changes of form brought 

 about by various causes from within or from without ; and the 

 simpler the organism which we select, the changes will be the 

 more rapid and the more clearly seen. Hence we resolved to 

 restrict our studies to one class, at most, each winter. 



The great use of that splendid instrument, the microscope, 

 is to help us to understand and interpret nature. To get 

 ideas as to how nature works should be our aim, and if we 

 cannot interpret her deeper meanings ourselves, the microscope 

 will greatly help us to understand the interpretations abler 

 men are giving of them. In biology, the great battle-field 

 where the heroes of our time join in combat is the field of the 

 microscope. There the modern Achilles challenges the modern 

 Hector, not over the dead body of a Patroclus, but over the 

 most elementary organism, the living cell ; and the Troy which 

 is to fall is that minute citadel of the elementary forces of 

 life, the nucleus. When that citadel surrenders, when its 

 workings are explained, it will be one of the greatest victories 

 ever achieved — a victory due, as all such great victories are, 

 to patient investigation and reasoning. Moreover, the nucleus 

 has the most important part to play in fertilisation, in cell- 

 division, very probably in cell-nutrition, and it may be the 

 bearer of hereditary qualities, and so have the shaping of the 

 destinies of the organism. 



One of the best books on microscopic work ever written is 

 Strasburger's — I mean, the German original, not the transla- 

 tion, which has been boiled down for examination purposes. 

 Strasburger published an edition of his ' Botanisches Prakti- 

 cuni' in 1884, and another has just been issued. The differ- 

 ence between the two editions, although they go over quite the 



