Junk 20, 1902.] 



SCIENCE. 



991 



varieties than in those that mature later. Thus 

 it is very common for Japanese wheats to be 

 infested with smut when introduced into this 

 country, and Japanese varieties are always 

 quite early in ripening. Now, as the tendency 

 of dryness and heat is to produce early ripen- 

 ing of plants, it appears that there may be 

 some relation between these parallel facts, and 

 the question is a very interesting one as to why 

 these conditions exist. As a rule the smut is 

 propagated by germinating in the ground with 

 the grain itself, infecting the young plant at 

 that time and growing up through the plant as 

 the plant grows, finally breaking out at the 

 surface in the wheat head. One of two 

 things therefore it seems may be true, either 

 that the abnormal condition of the plant pro- 

 duced by its infection with the smut causes 

 the plant to ripen earlier, or, on the other hand, 

 that the early maturity of the plant allows the 

 smut to work its way to the surface before 

 the plant has grown entirely beyond it. Many 

 observations seem to show that the latter is 

 true, although it is by no means established. 

 The tendency in dry seasons and in early ri- 

 pening is always to produce more fruit or 

 grain and less of the vegetative portion of the 

 plant. As the smut finally produces its spores 

 at the surface in the head, this condition 

 would naturally favor the maturity of the 

 smut. On the other hand, in later ripening 

 sorts and in moister regions or seasons of 

 greater moisture, the growth of the plant 

 being more rapid and the maturity of the 

 fruit occurring later, the plant is enabled in 

 a sense to outgrow the development of the 

 smut. 



A portion of the evening was devoted to a 

 symposiuna on 'Environment as a Factor in 

 Natural Selection,' the discussion being led by 

 Messrs. W. J. Spillman and H. J. Webber. In 

 the discussion Professor Spillman stated 

 that environment is not only a factor in nat- 

 ural selection ; it is the whole of it. It is more 

 than this, for it is a factor in variation. As 

 stated, therefore, the subject covers the whole 

 field of natural selection. It is probable that 

 natural selection has been overworked, and par- 

 ticular attention is called to the fact that 

 much, perhaps most, variation is neither useful 



nor harmful, and therefore not amenable to 

 the influence of natural selection. If this is 

 true a great deal of what we see in living 

 organisms is not due to natural selection, but 

 merely to fortuitous variation, perhaps to 

 mutations, as De Vries would have us believe. 



It is really change of environment that is 

 important in natural selection. These 

 changes are frequently favorable in that they 

 remove a condition which made selection more 

 strict. Examples of these are common in the 

 case of organisms transplanted to a new habi- 

 tat, where their natural enemies are absent. 

 Under such conditions variations become per- 

 missible that were not possible under the old 

 conditions, and what was before an unimpor- 

 tant species may assume a very important 

 place in the economy of nature. 



Mr. Webber stated that while the majority 

 of variations induced directly by the influence 

 of environment are not inherited ; nevertheless, 

 the influence of environment serves to destroy 

 those individuals which do not vary in the 

 direction of adapting themselves to the envi- 

 ronment. It is only those individuals, therefore, 

 which possess desirable variations that are 

 able to produce seed for the next genera- 

 tion. The action of the environment in the 

 next generation would be exactly the same, 

 those plants only which vary in the direction 

 of fitting themselves to the environment being 

 able to survive and produce seed. In this 

 way natural selection would eliminate such 

 variations as were unfitted to the environment, 

 so that only those plants best fitted would 

 propagate. This action continued through 

 several years would eventually result in ren- 

 dering hereditary the characters fitted to the 

 environment. Herbert J. Webber, 



Corresponding Secretary. 



DISCUSSION AND CORRESPONDENCE. 

 WHAT IS NATURE STUDY? 



There seem to be many conflicting defini- 

 tions in attempts to answer the above question. 

 Here are two examples: "Nature study, as 

 used in this paper, is understood to be the work 

 in elementary science taught below the high 

 school — in botany, zoology, physics, chemis- 

 try and geology. We should aim to defme re- 



