130 THE POPULAR SCIENCE MONTHLY 
but there is possibly a variation in other organs, such as the leg or 
tarsus, but it is difficult to obtain reliable Seeracare on some of 
these parts. The most vigorous nestling (No. 1) more than doubled 
in weight on the first day, more than trebled on the second, and more 
than quadrupled on the third, while on the twelfth day, when it left 

Wie, 29. YoOunG Cyparpirpd, No, 1 of table, shortly after hatching, lying on side, 
cicatrix of umbilicus showing on abdomen; weight 5 grams. August 10, 1901. 
the nest it had increased its initial weight seventeen-fold. What ten 
days will do for the young cedarbird on the score of appearance may 
be seen by comparing Figs. 29 and 30, the first of which shows nestling 
No. 1 when about two hours old. The data’on which these curves are 
based are given in the following table. 

Fic. 30. THE SAME CEDARBIRD (on left) as shown in Fig. 29, ten days later with 
birds Nos. 2 and 8 from the same nest. All show the crouching tendency, in evidence 
of fear. 
Kuhlmann,” who has recently published an interesting study of the 
development of the instincts and intelligence in certain altricious birds, 
in particular the turtle dove, the brown thrush and the red-wing 
blackbird, finds the rate of growth quite similar to that shown for the 
2 The Psychological Review, Monograph Series, No. 44, November, 1909. 
