Domesticated animals and plants; a Domesticated animals and plants; a brief treatise upon the origin and development of domesticated races, with special reference to the methods of improvement domesticatedanim00dave Year: 1910 13 DOMKSrUA IKI) AM) I' The stooling,' of i;rain is a case of branching at the base and is a real doubling, as are the four-, five-, or six-leaved clovers. The whole matter of doubling is, of course, the result of an extra cell di\ision at the lroper point,âan abnormality tliat is some- times hereditar\- Ixit oftener not, though a strong tendenc)' exists
Domesticated animals and plants; a Domesticated animals and plants; a brief treatise upon the origin and development of domesticated races, with special reference to the methods of improvement domesticatedanim00dave Year: 1910 13 DOMKSrUA IKI) AM) I' The stooling,' of i;rain is a case of branching at the base and is a real doubling, as are the four-, five-, or six-leaved clovers. The whole matter of doubling is, of course, the result of an extra cell di\ision at the lroper point,âan abnormality tliat is some- times hereditar\- Ixit oftener not, though a strong tendenc)' exists for an\' i:)h\-siological habit proceeding from internal Fig. 22. A hand- shaped corncob showing a tendency to branching of the ear, not at all un- common causes to become hereditary. Fusingof parts. Ouite the oppo- site of doubling is the fusing or joining of two parts into one. Thus the tw< kidneys may be joined at one end, making the horseshoe kidne}-. A pair of horns may be compounded into one. Two fingers of the human hand or the two toes of the pig may be united into one. When unit characters get mis- placed. Perhaps the most remarkable fact of development and differentia- tion is seen when a normal struc- ture develops in an abnormal place. Thus occasionally a tooth will develop roebuck are united into a single 1 f r .1 ii T ,1 beam for a considerable distance, m the roof of the mouth, as if the fenvards they germ of it had in some waâ got After Uatcson misplaced but was able to grow in its new place, like a tree that is transplanted. Sometimes the eye of an insect will develop not as an eye but as an antenna. 1 These are the so-called solid- or mule-hoofed hogs. This abnormality- arises frequently and may be readily propagated, as it happens to be fairly hereditary. See ' Principles of Breeding,' pp. 55, 66.
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