28 POULTRY FOR PROFIT 
the appearance of the interior of the egg. This 
can be done “by making a hole in a box, that 
will fit over a light or lamp, and then holding * 
the eggs up to the light, showing through the 
hole, which should be in line with the flame. 
If the egg appears clear, free from any dark 
spots, then the egg can be taken out of the 
incubator,, as it is not fertile, and will not 
hatch. However, if the egg shows a dark spot, 
about the size of a bean, and you can detect 
small blood vessels running from it, then you 
may be assured that the egg is coming along in 
good shape, and will hatch out in due time. 
With these points well in mind, one will 
have little difficulty in properly running an in¬ 
cubator, providing he has a reliable machine 
to begin with. Of the matters considered in 
this chapter, probably the most important fac¬ 
tor of all is the constant maintenance of a uni¬ 
form temperature. Now, then, let us consider 
that the chicks are pipping the shells and are 
ready to start out in life. We will therefore 
consider the care of the chicks in the next 
chapter, until they are able to care for them¬ 
selves. 
