Walter Frank Raphael Weldon. XX1X 
only piece of work on invertebrate embryology, “The formation of the Germ 
Layers in Crangon vulgaris.” This contains a clear account of the early 
stages of segmentation, and the building up of the layers of the shrimp, 
illustrated by excellent figures. And here it may be mentioned that his 
power with the pencil was not that of the mere draughtsman, accurate in 
detail but often lifeless; he was an artist by instinct, and he had the keenest 
pleasure in drawing for its own sake. 
December, 1890, closed the Cambridge work; Weldon now itiboedaea 
Ray Lankester in the Jodrell eeu eseone ta at University College, London. 
In June he had been elected a Fellow of the Royal Society. 
It has been seen that the years between Weldon’s degree and his first 
professoriate were years of intense activity. He was teaching many things, 
studying many things, planning many things. His travels perfected his 
linguistic powers, and his fluency in French, Italian, and German was soon 
remarkable. , 
A word must here be said as to the transition which took place during the 
“Wanderjahre” in Weldon’s ideas. He had started, as most of the younger men 
of that day, with an intense enthusiasm for the Darwinian theory of evolution, 
but he realised to the full that the great scheme of Darwin was onlya working 
hypothesis, and that it was left to his disciples to complete the proofs, of 
which the master had only sketched the outline. Naturally he turned first 
to those methods of proof, morphological and embryological, which were being 
pursued by the biological leaders of the period, and it was only with time 
that he came to the conclusion that no great progress could be attained by 
the old methods. We have already seen that even before the appearance of 
“Natural Inheritance,’ his thoughts were turning on tbe distribution of 
variations and the correlation of organic characters. He was being led in the 
direction of statistical inquiry. The full expression of his ideas is well given 
in the first part of the “ Editorial,’ with which ‘ Biometrika’ started :— 
“The starting point of Darwin’s theory of evolution is precisely the 
existence of those differences between individual members of a race or 
species which morphologists for the most part rightly neglect. The first 
condition necessary, in order that any processes of Natural Selection 
may begin among a race, or species, is the existence of differences among 
its members ; and the first step in an inquiry into the possible effect of a 
selective process upon any character of a race must be an estimate of 
the frequency with which individuals, exhibiting any degree of 
abnormality with respect to that character, occur. The unit, with which 
such an enquiry must deal, is not an individual but a race, or a 
statistically representative sample of a race; and the result must take 
the form of a numerical statement, showing the relative frequency with 
which various kinds of individuals composing the race occur.” 
It was Francis Galton’s “Natural Inheritance” that first indicated to 
Weldon the manner in which the frequency of deviations from the type 
could be measured. 
