Page:Popular Science Monthly Volume 67.djvu/201

Rh produces offspring with ears of intermediate size, which sometimes stand erect and sometimes lop. (See Fig. 3.) The ear-characters which were so distinct in the parents have in this case lost their identity in the offspring, and apparently can not be recovered again in their original condition, for the offspring transmit to their young the blended character, rather than the extreme conditions found in their respective parents.

It has been thought until quite recently that hereditary processes in general were of this sort and that any result other than a blend was exceptional. But recent investigations do not bear out this idea.

Alternative inheritance is illustrated in a cross between the so-called Belgian hare and an albino rabbit. The Belgian hare is simply a gray-coated variety of the European rabbit, while albino rabbits are pink-eyed animals of the same species and have white hair; the Belgian is pigmented like the wild European rabbit, the albino is essentially unpigmented. A cross between the two produces offspring all of which have the pigmented or Belgian coat, none being albinos. Compare Fig. 3; in this case the parents were an albino and a brown pigmented animal, respectively. The young, nine in number, were all black pigmented, like the one shown in Fig. 3.

The effect of crossing a pigmented rabbit with an albino is similar to that produced when two pieces of glass, one transparent, the other opaque, are held up together. We see only the opaque one. Nevertheless, the two conditions have not blended; each retains its original