34 Walter Frank Raphael Weldon. 1860—1906. 
In the second memoir Weldon sought for demonstration of a like periodic selection 
in the C. itala he had collected from the public walks round the Citadel of Brescia. 
He failed, however, to trace it, and was forced to conclude that G. itala is either 
not now subject to selective elimination for this character, or is multiplying at 
present under specially favourable conditions at Brescia, or again, as both young 
and old were gathered in early spring, after their winter sleep, that elimination 
takes place largely during the winter, and " that individuals of the same length, 
collected in the autumn, at the close of their period of growth, might be more 
variable than those which survive the winter." 
Quite apart from the results reached, Weldon's papers are of the highest 
suggestiveness. Does selection take place between birth and the adult or repro- 
ductive stage ? This is the problem which everyone interested in Darwinism 
desires to see answered. But to answer it we need to compare the characters of 
the organisms at the same stage of growth, for these characters are modified by 
growth. How is it possible to compare a sample of the race at an early stage, 
with its adult sample ? The problem of growth, to be studied only under 
conditions of captivity, possibly modifying the natural growth immensely, had 
made the crab investigation an extremely complex one. Weldon solved the 
difficulty by the brilliant idea that the snail carries with it practically a record of 
its youth. If the wear and tear of the outside of the shell to some extent 
confuses the record there, a carefully ground axial section will reveal by the lower 
whorls the infancy of the organism. Hence the days given to experimental 
grinding, the training in manipulation and the final success, and then the steady 
work, grinding and measuring a few specimens a day, till the necessary hundreds 
were put together ; the laborious calculations not in the least indicated in the 
papers — the arithmetical slips with bad days of depression, and the completed 
result : the illustration of how shells may be used — by those who will give the 
needful toil — to test the truth of the Darwinian theory. 
The summer of 1899 found the present writer at Great Hampden on the 
Chilterns, working at poppies and developing a theory of honiotyposis, namely, the 
quantitative degree of resemblance to be found on the average between the like 
pai'ts of organisms. W^eldon, who came over from Oxford to dredge the ponds and 
to discover Clausilia by the White Cross at Monks Risborough, provided the 
criticism, suggestion, and encouragement, in which he never failed* : 
" You have got hold," he wrote, after returning to Oxford, " of the big problem which all poor 
biologers have been trying for ever so long. I wish you good luck with it." 
The collection and reduction of material were on a larger scale than had been 
previously attempted, and the memoir was not presented to the Royal Society 
until the October of the following year (1900). It was soon evident that the 
attitude of the Society with regard to biometry was undergoing considerable 
change. The meeting of November 15 and the discussion that took place on the 
* His aid in the second part — Homotyposis in the Animal Kingdom, shortly to be published, — was 
even more substantial. 
