556 



SCIENCE. 



[N. S. Vol. XXIV. No. 618. 



material in a region at that time thousands 

 of miles from any other embryologist or 

 morphological zoologist. The work could be 

 done nowhere else, but try as I might, not a 

 cent could I secure from anywhere to support 

 me in my work.'^ The result of that work 

 was, aside from smaller papers describing new 

 species, etc.: 



1. ' On the Precocious Segregation of the 

 Sex Cells in Micrometrus aggregatus Gib- 

 bons,' Journ. Morph., Y., pp. 480-492, 1 plate. 



2. ' The Fishes of San Diego,' Proc. U. S. 

 Nat. Mus., XV., pp. 123-1Y8, 9 plates. Giving 

 spawning seasons and embryology, as well as a 

 list of San Diego fishes. 



3. * On the Viviparous Fishes of the Pacific 

 Coast of North America,' Bull. TJ. S. Fish 

 Comm. for 1892, pp. 381-478, 27 plates. 



4. ' Sex-differentiation in the Viviparous 

 Teleost Cymatog aster' Arch. f. Entwickel- 

 ungsm.,lY., pp. 125-179, 6 plates. 



A request for fifty cents a day while work- 

 ing in California was declined by one of the 

 government bureaus. A request for assistance 

 from two other institutions was declined. 



The article ' On the Viviparous Fishes ' was 

 sold for $100, not quite twice as much as had 

 been paid to draw one of the figures submitted 

 to illustrate it. It is thus that scientific work 

 has been encouraged in the past. The article 

 was a fragment, and the viviparous fishes still 

 await a worker who must he in the 'field* 

 among those fishes. Wallace long ago pointed 

 out that individual workers in the field do 

 proportionately vastly more than big, expen- 

 sive government expeditions. Just as surely 

 vastly more will be accomplished if individual 

 workers are subsidized to do their work where 

 they can do it best than if they are herded at 

 Washington. 



The most urgent need is temporary or per- 

 manent research professorships : appointments 

 made for specific work of men who will receive 

 their pay from the appointing institution, who 

 are responsible for all of their time and results 

 to the appointing institution, but who carry 

 on their work in their home institution or 



^ Thirty odd dollars I spent in incidentally 

 picking up rare or new species of fishes were re- 

 funded later. 



wherever else their work can be done to best 

 advantage. Carl H. Eigenmann. 



THE MUTATION THEORY IN ANIMAL EVOLUTION. 



The question of the origin of species is 

 that of the origin of specific characteristics 

 or differential marks. According to one the- 

 ory they arise gradually by accumulations of 

 the order of fluctuations. According to the 

 other they arise suddenly and completely as 

 mutations. The former theory explains cases 

 in which species are connected by intergrades. 

 The latter best explains discontinuity in spe- 

 cies; without it a subsidiary hypothesis to 

 account for observed discontinuity is neces- 

 sary. 



The first reading of de Vries's great work 

 'Die Mutationstheorie ' carried a conviction 

 to the minds of many zoologists as well as 

 botanists that the truth of the discontinuity 

 theory — ^which has long been urged under 

 other names — had been insufficiently recog- 

 nized. Of late opposition is appearing and 

 the mutationist is led to reexamine the 

 grounds of his faith. One of the most vigor- 

 ous of the reactionists is Merriam^ (1906), 

 who concludes his address before the zoolog- 

 ical section of the American Association with 

 the words : " The theory of the origin of spe- 

 cies by mutation, therefore, far from being a 

 great principle in biology, as some seem to 

 believe, appears to be one of a hundred minor 

 factors to be considered in rare cases as a 

 possible explanation of the origin of partic- 

 ular species of plants, but, so far as known, 

 not applicable in the case of animals." 



The evidence for so sweeping a generaliza- 

 tion is to be looked for in the body of the 

 address and I have carefully reread and an- 

 alyzed his paper. He offers first certain gen- 

 eral objections to the mutation theory and 

 then cites eases supporting the alternative 

 theory of gradual modification. His general 

 objections do not seem to me to be important. 

 His query (p. 242) ' if sport variations are 

 less likely to disappear by reversion than are 



^ ' Is Mutation a Factor in the Evolution of the 

 Higher Vertebrates?' Science, XXIII., No. 581, 

 February 16, 1906. 



