An Introduction to a Biology 



according to which the greater number of generations a 

 given hybrid is from the first hybrid . . . the fewer pure 

 recessive and dominant forms is it likely to produce when 

 mated with another hybrid of its own generation." 



(1) For the very good reason that I did not then understand 



it : as I do now. 

 (2), (3,) (4) If " Law of Contribution " is put in the place 



of the terms 2, 3, and 4, this passage is quite true 



As it stands, it is nonsense. 



Perhaps, after all, the most complete example of this 

 confusion is to be found in Castle's writings ; it occurs in 

 his paper on Galton's and Mendel's Laws. He gives a Table 1 

 to show the difference between the Mendelian and Galtonian 

 prediction of the number of albinos produced by crossing 

 Japanese waltzing mice with albinos, together with the 

 actual numbers that occurred in von Guaita's well-known 

 experiment. 2 



I give the top two lines of the Table. 



Substitute Law of Contribution for Galton's Law, and 

 the idea conveyed by the Table is sensible and true. 



I will refer to one more passage in which Galton's Law 

 is used in the sense of the Law of Contribution : " Nach 

 Gallons Theorie muss jede Gamete, welche von einem In- 

 dividuum produziert wird, imstande sein, alle Merkmale der 

 Sippe, welcher es angehort, auf die Nachkommen zu iiber- 

 tragen ; es ist unmoglich, dass gewisse Gameten fur immer 

 von der Ubertragung gewisser Merkmale ausgeschlossen 



Castle, :03, p. 231. a Guaita, '98 :00. 



189 



