PLATE 3 
EXPLANATION OF FIGURE 
15 At the right is shown a normal untreated testicle of a white rat sur- 
mounted by a well-developed epididymis, which is partly obscured by fat. At 
the left is a radiated testis showing considerable atrophy. The single small lobe 
at the very bottom of the photograph represents the remains of the tail of the 
epididymis, the head and body of that part being completely missing. The 
animal was treated in utero on February 21, 1920, was born February 23rd, and 
was killed December 31, 1920. Dose = 1350 me.hrs. of gamma-ray irradiation. 
160 
