TRANSMISSION OF INDUCED EYE-DEFECTS U7 
and when the lens has a rich plexus of blood-vessels surrounding it, 
any lytic or toxic substance in the blood specific for lens material 
would have a good opportunity to attack it with maximal effect. 
For instance, such a substance could directly hinder increase in 
size through solution of one or more of the lens proteins. Or it is 
not unlikely that the sensitized fowl serum would form a precipi- 
tin with some of the lens protein. This may be the means by 
which the opacity of the lens is produced. A stunting of the lens 
would in all probability result in the production of a smaller eye- 
ball, inasmuch as the parts are so mutually related in develop- 
ment. 
The eye defect, once secured, does not always remain at a 
standstill in the affected individual, but may progress; or it may, 
at least, have associated with it conditions which lead to further 
changes in the eye. For example, individual 3A1, a male secured 
in one of the earliest experiments, had the lens of the left eye 
opaque, although the eyeball was but slightly less than normal 
size at the time the eyes opened some twelve days after birth. 
This eye not only did not keep pace in size with the other eye 
as the young individual grew larger, but actually retrogressed as 
if being acted upon by some kind of solvent. It became gradu- 
ally smaller, the ball collapsed and almost disappeared. At the 
present time, about three years later, there is practically no trace 
of an eyeball (pl. 1, fig. 83A1; pl. 2). The condition indicates 
that a solvent effect of some kind is in operation. Such post- 
natal degeneration occurred in several rabbits. 
LATER EXPERIMENT ON THE PRODUCTION OF EYE DEFECTS WITH 
LENS-SENSITIZED SERA 
In our later experiments much the same methods of procedure 
were followed as in those recorded in our first study (Guyer and 
Smith, 718). Fowls were sensitized with rabbit lens from four 
to six times at intervals of approximately a week, and were 
then left about ten days before killing. In most experiments the 
original method of injecting the pulped lens intraperitoneally 
was followed, though in a few cases the more difficult method of 
injecting the material directly into the femoral vein of the fowl 
