230 
IOWA ACADEMY OF SCIENCE Vol. XXIX, 1922 
species of turtle. When the turtle is digging her nest or de- 
positing her eggs she is not easily frightened so that it is possible 
to get very close to the animal and to use a flash light within an 
inch or two of the body. On several occasions a number of 
students at the Laboratory were able to watch the entire process 
from the time the turtle landed on the shore until it returned 
to the water again. This paper presents more or less in detail 
the events that took place in the little more than two hours 
occupied by the turtle in digging the nest, laying the eggs, and 
concealing the nest. 
SOCIOLOGY AS A SCIENCE 
HORNELL HART 
The term “social science” appears to be taken seriously neither 
by scientists nor by sociologists. Conditions in social research 
have justified that lack of confidence, but an increasing group 
has set about the systematic collection of data on specific social 
problems and is reaching results capable of objective verification. 
Three recent studies of the Sociological Division of the Iowa 
Child Welfare Research Station illustrate this tendency. One of 
these measures and describes by statistical methods the selective 
emigration which threatens to impoverish socially certain rural 
areas of the state. A second study develops by means of partial 
regression equations the fact that the intellectually and economi- 
cally successful classes in Iowa have much lower net fecundities 
than the unsuccessful and the ignorant. A third investigation is 
developing methods of quantitative analysis of social attitudes 
and interests. 
Sociological Division, Iowa Child Welfare Research 
Station. 
CHANCE IN DEVELOPMENT AS A CAUSE OF 
VARIATION 
P. W. WHITING 
Variation is ordinarily considered as due to internal hereditary 
factors interacting with external environmental factors during 
development. In experimental work with a parasitic wasp con- 
siderable variation has been found in certain pure-bred stocks 
kept at certain constant environmental conditions. Either at 
other constant environmental conditions or in other pure-bred 
