September 8, 1921^ 



-.NATURE 



57 



by chemical principles in the commonplace opera- 

 tions of daily life. This is done by Dr. M. O. 

 Forster in his presidential address to Section B 

 (Chemistry), entitled "The Laboratory of the 

 Living Organism." 



Illustrations are drawn from the marvellously 

 interwoven stages of digestion and assimilation, 

 from the purely chemical potentiality distinguish- 

 ing animals from plants, and from the chemistry 

 of the nucleic acids, the constitution and degrada- 

 tion of which have now been clarified by researches 

 extending over the past fifty years. The present 

 state of knowledge embracing chlorophyll and 

 haemoglobin is discussed, and is followed by a 

 survey of the anthocyans, the pigments of 

 blossoms and fruits. Attention is directed also to 

 the diverse activities of micro-organisms and the 

 need for systematic inquiry into the capabilities of 

 those humble practitioners of the chemical art. 



It is claimed that, by simple readjustments, the 

 general scheme of secondary education could be 

 made to include the principles of chemistry, 

 physics, mechanics, and biology in quantity suffi- 

 cient to render all intelligent citizens able to 

 recognise, at least superficially, the miraculous 

 transformations in which they take part, and 

 which surround them on every side. Such 

 a result would not only add enormously to 

 the aesthetic value of life, but would provide 

 the sympathetic and intellectual background 

 for those who will, in the near future as 

 history counts time, be called upon to surmount 

 the real danger wath which civilisation is 

 threatened, namely, the continued failure of 

 ■governments and people to realise that the worst 

 enemy of man is Nature ignored or misunderstood^ 

 whilst his best friend is Nature studied and con- 

 trolled. 



Experimental Geology. 



Dr. J. S. Flett's presidential address to 

 Section C (Geology) deals with the subject of ex- 

 perimental geology. Of recent years a great and 

 increasing amount of research has been done in 

 determining the behaviour of molten silicates and 

 other minerals when they are cooled and allowed 

 to crystallise. By means of the electric furnace 

 such experiments are now comparatively easy, 

 and the electric pyrometer ensures ■ accurate 

 measurement of temperature. Many rock-forming 

 minerals can thus be studied as regards their 

 genesis and the conditions under which they are 

 stable. Quartz, felspar, diopside, enstatite 

 olivine, nepheline, woUastonite, tridymite, and 

 many other components of igneous rocks can be 

 produced in the laboratory. The action of gases ^ 

 can also be determined in apparatus specially 

 designed to resist great pressure at high tem- 

 peratures. Microscopic examination of the pro- 

 ducts has reached a stage of minute accuracy 

 which greatly facilitates the interpretation of the. 

 results. We might almost regard this as a 

 " new " petrology, but it is really a development of 

 a method of inquiry which was initiated by Sir 

 James Hall in the early years of the nineteenth 



NO. 2706, VOL, 108] 



century. Hall made experiments to prove that 

 by slow cooling a molten basalt would consolidate, 

 not as a glass, but as a crystalline rock. After- 

 wards he made a laborious investigation into 

 the behaviour of chalk and limestone when 

 heated in closed vessels, and succeeded in obtain- 

 ing a crystalline marble. His results have been 

 much discussed, and of recent years his experi- 

 ments have been repeated with all the refinements 

 of the modern laboratory. Hall's position as the 

 founder of experimental geology has been vindi- 

 cated, and his work remains a classic in this 

 department. 



Heredity, Environment, and Evolution. 



Prof. E. S. Goodrich points out in his 

 address to Section D (Zoology) that it is 

 nearly one hundred years since Charles Darwin 

 began his scientific studies in the University of 

 Edinburgh. Certain problems relating to Darwin's 

 doctrine of evolution still remain unsolved, and 

 it is useful from time to time to re-examine the 

 very foundations on which our theories are laid. 



In trying to answer the question why some 

 characters are inherited and others not, inherit- 

 ance is defined as the reappearance in the offspring 

 of a character possessed by the ancestor. Its 

 constant reappearance is shown to be due neither 

 to its age nor to its importance, but to the presence 

 of both the germinal factors of inheritance and 

 the environmental conditions or stimuli which co- 

 operated in its formation in the parent. Characters 

 are all of the nature of responses to stimuli which 

 mould the course of metabolism. The factors 

 alone are transmitted from parent to offspring in 

 the germ-cells. The characters are produced anew 

 at every generation. We s"hould carefully distin- 

 guish between transmission and inheritance, and 

 it is clear that whereas factors may be transmitted, 

 characters as such never are. 



There is no difference in kind or value between 

 characters, and if some are inherited regularly 

 and others not, the distinction lies in the con- 

 stancy of the factors and conditions which give 

 rise to them. There is only one kind of chnr- 

 acter, but there are two kinds of variation — 

 modification due to change in the effective en- 

 vironmental stimuli, and mutation due to change in 

 the complex of germinal factors. These varia- 

 tions must not be confused, as is so often done, 

 with the characters that result from them. 



The perpetual growth reproduction and trans- 

 mission of the factors of inheritance (continuity 

 of the germ-plasm) are but one 'aspect of the con- 

 tinuity of the metabolic processes at the basis of 

 all the manifestations of life. Just as the various 

 steps in the metabolic process are dependent on 

 those which preceded them, so when an organism 

 becomes differentiated into parts these react on 

 each other and act as internal environmental 

 stimuli, calling forth further responses which may 

 modifv the first. From chains of interdependent 

 responses arise the power of individual adaptation 

 and self-regulation. W^hereas the lower organisms 



