244 Mendel's Laivs of Alternative Inheritance in Peas 
mosaic of smooth and spiny segments. On the other hand, D. stramonium of the 
spiny form, crossed with D. ceratocaula, which has a smooth fruit of different 
character, gave hybrids whose fruits exactly resembled those of D. stramoniuvi. 
Examples might easily be multiplied, but as before, I have chosen rather to 
cite a few cases which rest on excellent authority, than to quote examples which 
may be doubted. I would only add one case among animals, in which the evidence 
concerning the inheritance of colour is affected by the ancestry of the varieties 
used. Many people have crossed the various white, piebald and wild-coloured 
varieties of the rat {Mus decumanus), the closely similar varieties of the mouse 
(Mus musculus) have also been frequently crossed. In both rats and mice von 
Fischer (Nos. 10 and 11) says that piebald rats crossed with albino varieties of 
their species, give piebald young if the father only is piebald, white young if the 
mother only is piebald. Crampe (No. 8) finds that in either case the offspring are 
a mixture of piebald forms and albiuos. Results such as those which Crampe 
records in rats are commonly obtained when piebald and albino mice are paired ; 
but both Haacke (No. 17) and von Guaita (No. 16) find that when the ordinary 
European albino mouse is paired with the piebald Japanese "dancing" mouse, the 
offspring are either like wild mice in colour, or almost completely black. Again, 
Crampe says that when white and wild-coloured mice are crossed the offspring 
are invariably coloured like wild mice. CoUadon is reported by Provost and 
Dumas {Ann. Sci. Nat. I., 1824) to have obtained both albino and wild-coloured 
individuals from similar crosses, but no piebald individuals. 
These examples, chosen from many others which might have been cited, 
seem to me to show that it is not possible to regard dominance as a property 
of any character, from a simple knowledge of its presence in one of two individual 
parents. The degree to which a parental character affects offspring depends 
not only upon its development in the individual parent, but on its degree of 
development in the ancestors of that parent. A collection of cases which illustrate 
this point is given by Bateson (No. 1). 
III. — Tlie Hybrid Peas of the Telephone Group. 
If Mendel's statements were universally valid, even among Peas, the characters 
of the seeds in the numerous hybrid races now existing should fall into one or other 
of a few definite categories, which should not be connected by intermediate forms. 
In attempting to follow the results obtained by Tschermak and others I have 
carefully examined the seed characters of some twenty named varieties, and the 
present condition of many I have studied seems to me quite incompatible 
with the general validity of Mendel's statements. The aberrant behaviour of 
the race called Telephone has already been observed by Rimpau and Tschermak, 
and I have therefore endeavoured to learn the past history and the present 
condition of this Pea and the races allied to it. In my attempt I have received 
very great help from Messrs Carter and Co., who originated Telephone and its 
allies, from Messrs Sutton and Sons, and from Messrs Vilmorin-Andrieux and Co., 
