488 



SCIENCE 



[N. S. Vol. XXXIX. No. 1005 



lies in endowments either in connection 

 with universities, or through the establish- 

 ment of the specialized private institution. 

 That the problem of applied evolution 

 will eventually be solved there can be no 

 doubt. That it will occur in our generation 

 may only be expressed as a hope. 



L. B. Walton 



Kenyon College, 

 November 15, 1913 



TEE MUTATION MTTE 

 It has long been recognized both on the bot- 

 anical zoological sides, that sterility is a 

 notable characteristic of species crosses or true 

 hybrids. Where species are nearer to one an- 

 other their resultant cross is naturally less 

 sterile than when their affinity is more re- 

 mote. In the case of plants it is usually par- 

 ticularly easy to trace even slight evidences 

 of previous hybridization in the sterility and 

 abortive character of some of the spores or 

 poUen. In contrast to hybrids, genetically 

 pure species are characterized by pollen grains 

 or spores, as the case may be, which are all 

 perfectly developed. I have satisfied myseK 

 by a very extensive study of the spores and 

 pollen of liverworts, mosses, ferns (including 

 numerous genera of all the important families, 

 isosporous and heterosporous), lycopods, sela- 

 ginellas, quillworts, lepidodendroids, equiseta, 

 eycads, ginkgo, conifers (including numerous 

 genera of all the tribes), gnetales (all the 

 genera) and many dicotyledonous and mono- 

 cotyledonous angiosperms, that in good spe- 

 cies the spores or pollen is invariably perfect 

 morphologically, that is fully formed and hav- 

 ing normal protoplasmic contents. Known 

 hybrids on the contrary are characterized by a 

 greater or smaller number of abortive spores, 

 which have little or no protoplasmic contents. 

 Hayes, of Coimectiout, Pearl, of Maine, Emerson, 

 of Nebraska, Dean Davenport, Rietz and Smith, of 

 Illinois, are familiar to all interested in the appli- 

 cation of the principles of evolution. One often 

 conjectures, however, as to the extent to -which some 

 of the most valuable contributions are in reality 

 "by-products" of investigations meeting the ap- 

 proval of the ' ' Missouri ' ' type of legislator. 



This conclusion is by no means new but the 

 wide range of facts examined in the present 

 connection adds very materially to its 

 strength. It has been further noted that so 

 far as morphological conditions are concerned, 

 plants of genetic purity, even when grown, 

 under extremely abnormal conditions, as 

 exotics in greenhouses, etc., have perfect 

 spores or pollen. For example a conifer or a 

 cycad from Australia or Japan, grown in the 

 hothouse and producing its pollen in the 

 winter season, still shows the grains normally 

 developed morphologically, whatever may be 

 their physiological inefficiency. 



The bearing of the facts indicated in the 

 paragraph above is of great importance in 

 relation to the mutation hj^pothesis of De 

 Vries. This distinguished Dutch plant physi- 

 ologist, a little over a decade ago, published a 

 series of observations and generalizations 

 under the title of " Die Mutationstheorie." 

 His notable offering was the statement that 

 material of a species of (Enothera or evening- 

 primrose, referred by him to Seringe's (Eno- 

 thera lamarckiana, found growing spontane- 

 ously near Hilversum in Holland, was produc- 

 ing annually new species or as he preferred to 

 call them, elementary species. In 1904 Pro- 

 fessor De Vries was invited to lecture in the 

 University of California on his sensational 

 discoveries. The lectures were edited and pub- 

 lished later by the director of the Desert 

 Laboratory of the Carnegie Institution of 

 Washington, with the title of " Species and 

 Varieties, Their Origin by Mutation." Dr. 

 MacDougal thus became both in fact and figu- 

 ratively, the " vox in deserto clamantis," the 

 baptist of the gospel of mutation. His ex- 

 ploits with the syringe in the baptism and 

 production of new species of plants by intra- 

 ovarial injections appear further to render his 

 claims in this direction beyond question. As 

 secretary of the Botanical Society of America 

 and by his repetition and elaboration of De 

 Vries's cultures of (Enothera, be has done un- 

 questionably more than any one else to diffuse 

 the doctrine of mutation in North America. 

 It has in fact become so widely accepted on 

 our continent, that it has in many instances 



