Walter Frank Raphael WeMou. 1860 — 1906. 
41 
As Nebensachen, there are the mice and I very much want you to group the snails* in your 
own way — to see how far your grouping will bring them into a better form for the curve ! 
But Draha verna ought to be an example of the whole bearing of statistical methods upon 
systematic problems. I think it is rather important to begin this spring by collecting material 
for an analysis of the races round here, and a comparison of these with the types recognised 
by systematists. Learning these and their variability in this neighbourhood this spring, we can 
learn cotyledon characters and the characters of the first formed leaves in the Autumn — basing 
upon these a first set of hereditary correlations. 
Again, the statement that each of Jordan's species can be recognised at cm// stage in the life- 
Mstory of the -plant makes it necessary to woi'k correlations between cotyledon characters, 
autumn leaf characters, and spring characters. All this is work for lots of folk, and it is most 
important to get it properly planned now. Therefore, and for lots of other reasons try to 
come on Friday ! 
The Dog shall be washed for you ! " [Oxford, 22/2/02.] 
The reference in this letter to the mice indicates that that great piece of 
experimental work in heredity was now started. A study of the work of von 
Guaita had convinced Weldon early in 1901 that the cross between the European 
albino mouse and the Japanese waltzing mouse was not one which admitted 
of simple Mendelian description. In May, 1901, his letters contain inquiries 
as to Japanese mice dealers. During the summer and autumn the collection 
of Japanese mice was in pi'ogress. These mice were to be bred to test the purity 
of the stock ; during December about forty does had litters, and pure breeding 
went on until the autumn of 1902, when hybridisation commenced. The work on 
these mice was for two years entrusted to Mr A. D. Darbishire, but the whole plan 
of the experiments, the preparation of the correlation tables, and the elaborate 
calculations were in the main due to Weldon. On Mr Darbishire's leaving Oxford, 
Weldon again resumed personal control of the actual breeding arrangements, and 
from second hybrid matings carried on the work to the sixth hybrids' offspring. 
The work was nearing completion at his death, and through the energy of 
Mr Frank Sherlock the skins of the 600 pedigree mice forming the stud at 
that time have been dressed and added to those of the earlier generations. The 
reduction and publication of this material will, it is hoped, be not long delayed (33). 
Weldon had this work much at heart, and his letters during 1904 and 190.5 give 
many indications of the points he considered demonstrated. The experimental 
part of the work would have been nearly completed had not his whole thought and 
energy been directed from November, 1905, into another channel. 
From 1901 it is harder for the present writer to give a detailed account 
of Weldon's life, the co-editorship of Biometrika and common work brought them 
so continually into contact. In the early part of the summer there had been 
a hurried visit to Gremsmtihlen for young Clausilia ; Weldon on his return visited 
his co-editor at Througham in Gloucestershire bringing his Bruusvigaf, and there 
* H. nemoralis and H. horteiisis of which many hundreds had now been collected from various parts 
of England by Weldon and his helpers. 
+ The familiar mechanical calculator of the biometrician, the grinding sound of which (emphasised 
by the want of oiling in Weldon's case !) is the music which tells him how much his labours can be 
lightened. 
Biometrika v 6 
