128 



THE AMERICAN NATURALIST [Vol. L 



that, once in existence, many varieties obey the fundamental law of 

 reproduction that like tends to produce like; and their offspring ex- 

 emplify it by tending to exhibit the same deviation from the parental 

 stock as themselves. 



After further discussing the case, Huxley remarks (Op. cit. 

 p. 39) : 



Here, then, is a remarkable and well-established instance, not only of 

 a very distinct race being established per saltum, but of that race breed- 

 ing " true " at once, and showing no mixed forms, even when crossed 

 with another breed. 



Reaumur's ease of a Maltese couple having a hexadaetylous son, 

 three of whose four children were again hexadaetylous, also 

 comes in for Huxley's comment (p. 35 if.). The following dicta 

 on the subject of variation, from the same volume, are also worth 

 quoting : 



Indeed we have always thought that Mr. Darwin unnecessarily ham- 

 pered himself by adhering so strictly to his favourite " Nature non f acit 

 saltum." We greatly suspect that she does make considerable jumps in 

 the way of variation now and then, and that these saltations give rise 

 to some of the gaps which appear to exist in the series of known forms 

 (P. 97). 



I apprehend that the foundation of the theory of natural selection is 

 the fact that living bodies tend incessantly to vary-. This variation is 

 neither indefinite, nor fortuituous, nor does it take place in all directions, 

 in the strict sense of these words. ... A whale does not tend to vary in 

 the direction of producing feathers, nor a bird in the direction of de- 

 veloping whalebone (p. 181). 



The importance of natural selection will not be impaired even if fur- 

 ther inquiries should prove that variability is definite, and is determined 

 in certain directions rather than in others, by conditions inherent in that 

 which varies. It is quite conceivable that every species tends to pro- 

 duce varieties of a limited number and kind, and that the effect of 

 natural selection is to favour the development of some of these, while it 

 opposes the development of others along their predetermined lines of 

 modification (p. 223). 



From these and similar statements it appears evident that were 

 Huxley living to-day he could scarcely escape being classed as a 

 mutationist. 



R. Ruggles Gates 



