64 THE CALL OF THE HEN. 
down on head until you feel back of skull; when you feel back of skull 
with ball of thumb, then turn first joint of thumb down until thumb-nail 
fits in between end of skull and neck and well up against base of brain; 
then, while holding left hand and thumb as in Fig. 39, put forefinger of 
right hand at base of brain behind the ear, as in Fig. 39, between the 
neck and the skull and against the skull behind the ear, as in Fig. 39. 
Fic. 39—Showing thumb !/. of an inch ahead of forefinger; indicating hen is total- 
ly lacking in prepotency. (See Skull No. 4, Fig. 35.) 
The ear can readily be discovered by lifting up its hairy covering. The 
thumb-nail must be held perfectly straight across the neck, as in Fig. 39, 
and not sideways; and the forefinger must be held perfectly at right 
angles with the thumb, or the length of projection (arrow 1, Fig. 35) 
eer the base of the brain (arrow 4, Fig. 35) cannot be measured accu- 
rately. 
The reader will notice that my thumb-nail is ahead of my forefinger- 
nail in Fig. 39; this indicates that this hen is wholly lacking in the ability 
to transmit any redeeming qualities to her offspring, also that she has 
no desire for offspring. If this were a male bird, the eggs from his matings 
would be infertile. Fig. 40 shows thumb on line with forefinger. Mat- 
