I857-] VARIABILITY. 457 



is the more surprising to me, as generally I find any propo- 

 sition more easily tested by observations in botanical works, 

 which I have picked up, than in zoological works. I never 

 dreamed that you had kept the subject at all before your 

 mind. Altogether the case is one more of my many horrid 

 puzzles. My observations, though on so infinitely a small 

 scale, on the struggle for existence, begin to make me see a 

 little clearer how the fight goes on. Out of sixteen kinds of 

 seed sown on my meadow, fifteen have germinated, but now 

 they are perishing at such a rate that I doubt whether more 

 than one will flower. Here we have choking which has taken 

 place likewise on a great scale, with plants not seedlings, in 

 a bit of my lawn allowed to grow up. On the other hand, in 

 a bit of ground, 2 by 3 feet, I have daily marked each seed- 

 ling weed as it has appeared during March, April and May, 

 and 357 have come up, and of these 277 have already been 

 killed, chiefly by slugs. By the way, at Moor Park, I saw 

 rather a pretty case of the effects of animals on vegetation : 

 there are enormous commons with clumps of old Scotch firs 

 on the hills, and about eight or ten years ago some of these 

 commons were enclosed, and all round the clumps nice young 

 trees are springing up by the million, looking exactly as if 

 planted, so many are of the same age. In other parts of the 

 common, not yet enclosed, I looked for miles and not one 

 young tree could be seen. I then went near (within quarter 

 of a mile of the clumps) and looked closely in the heather, 

 and there I found tens of thousands of young Scotch firs 

 (thirty in one square yard) with their tops nibbled off by the 

 few cattle which occasionally roam over these wretched heaths. 

 One little tree, three inches high, by the rings appeared to be 

 twenty-six years old, with a short stem about as thick as a 

 stick of sealing-wax. What a wondrous problem it is, what 

 a play of forces, determining the kind and proportion of each 

 plant in a square yard of turf! It is to my mind truly won- 

 derful. And yet we are pleased to wonder when some animal 

 or plant becomes extinct. 



I am so sorry that you will not be at the Club. I see Mrs 



