Karl Pearson 
411 
TABLE VI. 
Homotyposis in the Red Blood Corpuscles of Frog and Toad. 
Character 
Number of 
Individuals 
Number of 
Pairs 
Kaw Value 
Corrected 
Value 
Table 
B. temporaria, Adult . . . 
R. temporaria. Tadpoles 
B. vulgaris, ToeLdTpoWs... 
Length 
Index 
Length 
Index 
20 
71 
61 
29 
49,000 
42,600 
36,600 
17,400 
•153+ -021 
•333+ 014 
•186 + •on 
•121 + ^025 
?* 
•405 
•206 
•134 
G, p. 417 
H, p. 418 
I, p. 418 
J, p. 419 
corpuscle with growth, we get somewhat higher values. If r be the raw cor- 
relation coefficient, rj the correlation ratio between the character and stage of 
growth, R the corrected correlation and m the number of homotypes used, then 
I have shown thatf : 
1-^'- («i-l)(l-T)' 
From this formula are found the " corrected " values given in the last column 
of the table. It will be seen that while the changes are in the right direction, 
they do not raise the homotyposis to the value we might have anticipated from 
other published and unpublished homotypic results. We therefore conclude that 
while there is undoubtedly individuality of a homotypic character in the blood 
corpuscles of the species dealt with, there are very probably differentiating factors, 
not yet studied, which have not been allowed for when we merely correct the corre- 
lations on the basis of body growth. The suggestion that naturally arises is tliat 
the cell undergoes changes not only in relation to bodily growth, but probably 
in relation to its own life. 
(6) Conclusions. 
The object of the present paper will be fulfilled if it shows that : 
(i) the size and form of the blood corpuscle is related to the life history of 
the organism to which it belongs ; 
(ii) there is a quite sensible individuality in the blood corpuscles of the 
same individual, if it be not so intense as the mean value which has been found 
for the homotyposis of purely homologous organs ; 
(iii) there is a wide field here for biometric inquiry, but it needs much 
labour and persistence, if the sample is to be 50 — 100 corpuscles in each of 400 
to 500 individuals. 
* No body measurement was taken on these frogs, which were described merely as adult ; thus no 
correction for size can be made. 
t "On Homotyposis in Homologous, but differentiated Organs." Pioc. R. S. Vol. 71, pp. 303—4 and 
footnote. 
