654 The American Naturalist. [August, 
Geddes expresses this principle in physiological terms of 
metabolism, that anabolic (constructive) conditions produce 
females, while katabolic (destructive) conditions produce males. 
think we may now safely eliminate the factor of sex from 
our calculations upon the problem of heredity, and thus rid 
ourselves of one of the oldest and most widespread fallacies. 
We shall thus, in using the terms “ paternal” and “ maternal” 
imply merely the distinction between two lines of family 
descent. 
The Theory of Reduction.—This leads us back to the signifi- 
cance of the polar bodies. Van Beneden’s discovery that these 
sree 
Drege" o 
OSOE e = 
fo) os 
S225 (CY 2: 
Merion 
sone Heo RS 
eras 
Ofi ao 0°, oe 
o 
Wo e 0; 
Weismann after Hertwig.) A, prae germ-cell in o c germ-la chromatin rods; B, 
Ovum mother-cell—8 rods ; C-D, First polar body extruded; E, Splitting rat at — body. Ovum 
still contains 4 rods ; F, Second polar body extruded ; at mature with 2 rods 
bodies contained chromatin led gradually to the view that they 
were not fragments of the ova, but represented minute mor- 
phologically complete cells. Bütschli showed that they were 
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ae Saye mn aes At z Aa ia es Piet: 
EE ee AE RA EPI O RS Lae CE Be ee E ee IA Pee S Rees 
