April 7, 1905.] 



SCIENCE. 



543 



vegetative development and seed-produc- 

 tion, facilitates the activation and appear- 

 ance of latent qualities, and the inference 

 lies near at hand that such conditions also 

 participate as causes in the original organ- 

 ization of new unit-characters, or in 

 changes in these entities. We conclude, 

 therefore, that favorable environment pro- 

 motes the formation of new species as sug- 

 gested by Korshinsky, and that new species 

 do not arise under the stress of infra- 

 optimal intensities of external factors as 

 proposed by Darwin. 



Furthermore, it has been found that cer- 

 tain qualities arise and disappear more 

 numerously, and presumably more readily, 

 than others, in a mutating strain. Thus 

 those embodied in the mutants ohlonga, 

 lata and nanella find external realization in 

 many more individuals than those which 

 constitute the differentiating features of 

 ruhrinervis, scintillans, gigas, elliptica, 

 suhovata and others. 



Again, the inspection of the cultures 

 made in Amsterdam and New York dem- 

 onstrates that the last-named locality 

 offers more favorable soil and climate for 

 the evening-primroses. Correlated with 

 this I am able to report that careful atten- 

 tion to the cultures has resulted in an in- 

 crease of the proportion of mutants from 

 the five per cent, maximum of de Vries to 

 more than six per cent, in the last season, 

 in the American cultures, and to say that 

 some forms Avhicli did not reach maturity, 

 and others which did not oc?ur in Amster- 

 dam, may find in New York a climate in 

 which they may carry out their entire de- 

 velopment. The cultures of Lamarck's 

 evening-primrose now being carried on in- 

 clude fourteen recognizable mutants, and it 

 is pertinent to state that I have mutants of 

 other species which will be duly described 

 after they have completed a cycle of de- 

 velopment. 



All components of the environment may 



not be taken to be of equal value in the 

 induction of new qualities, and I by no 

 means wish to give the impression that the 

 problem is on the point of being solved, 

 but our hopes have been raised to the high- 

 est pitch that we may soon be able to dis- 

 cern the factors more or less directly con- 

 cerned. 



To be able to bring the causes that are 

 operative in the formation and structural 

 expression of qualities, i. e., the moving 

 forces of evolution, within the range of ex- 

 perimental investigation would be a tri- 

 umph worthy the best effort of the natural- 

 ist ; in that it would give us the power to 

 give new positions to qualities and thus to 

 produce new organisms, its importance 

 would rank well with that of any biological 

 achievement of the last half century. 



SCIENTIFIC BOOKS. 

 The Zoological Record, Vol. XL., being rec- 

 ords of zoological literature relating chiefly 

 to the year 1903. Edited (for the Zoolog- 

 ical Society of London) by DAvm Sharp. 

 London. 1904. [Published early in 1905.] 

 The Zoological Record, which has now been 

 published for forty years, is simply invaluable 

 to the working zoologist. This statement 

 seems so trite as to be ridiculous, but the fact 

 is not known to some of those who most need 

 the work. Some time ago I received letters 

 from a well-known naturalist, asking for in- 

 formation concerning a group, the North 

 American species of which he was cataloguing. 

 In my replies I referred to the Zoological 

 Record; but the answer came back: 'Do not 

 refer me to the Zoological Record, it is not 

 accessible to me.' I do not cite this as an 

 unusual case; on the contrary, one continually 

 observes that writers have not seen the Record, 

 and have missed various things in conse- 

 quence. 



Consider for a moment what a time-saver 

 the Record is, and how many oversights it 

 prevents. Suppose I want to know about some 

 genus of animals, literally any genus that 

 may be mentioned; in half an hour I can find 



