98 



SCIENCE 



[N. S. Vol. XLIII. No. 1099 



are at present affiliated with the imiversity 

 and located downtown. A new dental school 

 building is about to be constructed. 



The sum of a quarter of a million dollars 

 has been given by Mrs. Kussell Sage to the 

 Emma Willard School in Troy to found a de- 

 partment of domestic and industrial art to be 

 known as the Russell Sage School of Practical 

 Art. The new department will occupy the 

 buildings recently vacated by the school on 

 the completion of new buildings made possible 

 by a gift of $1,000,000 from Mrs. Sage in 1907. 



We learn from Nature that Mr. Patrick 

 Alexander, known by his pioneer work in aero- 

 nautics, has made over to the headmaster of 

 the Imperial Service College, Windsor, the 

 sum of £10,000 " for the furtherance of the 

 education of boys of the Imperial Service Col- 

 lege, i. e., for the training of character and the 

 development of knowledge." Mr. Alexander 

 had given to the college an aero-laboratory 

 and equipment about five years ago. 



Dr. Irving E. Melhus, formerly pathologist, 

 office of cotton and truck diseases of the Bu- 

 reau of Plant Industry, has assumed charge of 

 the work in plant pathology in the Iowa State 

 College. 



DISCUSSION AND CORRESPONDENCE 



GENETIC FACTORS AND ENZYME REACTION 



In spite of the great progress in the knowl- 

 edge of facts in genetics the nature of genetic 

 factors may well be regarded as unknown. 

 Various theories have been proposed but only 

 a few steps have been made to attack the prob- 

 lem experimentally. Those who approached 

 it from the physiological-chemical side all 

 seem to agree that the unit-factors are to be 

 compared in some way to enzymes (Loeb, 

 Robertson, JMoore, Bateson, Riddle, etc.) or 

 expressed more generally " that the hereditary 

 factor ... is a determiner for a given mass 

 of certain ferments " (Loeb and Chamberlain, 

 1915).^ At first sight there are not many ways 

 visible of an experimental attack on this 

 problem. One is described by Loeb and 

 Chamberlain in the following words : 



1 Jour. Exp. Zool., Vol. 19, 1915. 



If we wish to carry this view (with which we 

 sympathize) beyond the limit of a vague state- 

 ment, we must either try to establish the nature of 

 these compounds by the methods of the organic 

 chemist, or we must use the methods of general 

 or physical chemistry and try to find numerical 

 relations by which we can identify the quantities 

 of the reacting masses or the ratio in which they 

 combine. 



Some steps in this direction have been made 

 by Loeb, Robertson and Ostwald, who tried to 

 prove that the phenomena of growth may be 

 understood as autocatalytic reactions; by 

 Moore, who compared the velocity of develop- 

 ment of a dominant character in homozygotes 

 and heterozygotes ; by Loeb and Chamber- 

 lain, who followed the more indirect way of 

 proving the enzyme-reaction-like basis of a 

 certain kind of fiuctuating variability. It is 

 further known that Miss Wheldale and Keeble 

 are approaching the question by a direct study 

 of the chemistry of plant pigments in hybrids 

 of known constitution and quite recently a 

 very interesting paper on hair-pigments in 

 rodents has been published by Onslow.^ 



For some time I have had similar ideas in 

 regard to these questions in connection with 

 genetical experiments, approaching the sub- 

 ject from quite an imexpected side. It was 

 not the intention to publish them before the 

 entire work was finished. But as this will take 

 some years longer and the subject is becoming 

 meanwhile more popular, it might be advisable 

 briefly to point out the ways in which I 

 reached conclusions very similar to those of 

 Loeb, etc. 



The genetical reaction which is concerned 

 primarily in my experiments is the pigmenta- 

 tion of the wings of moth. Its dependence 

 upon genetic factors is well Iniown and its 

 chemical character — the amino-acid-oxydase 

 reaction — is comparatively clear. In one set 

 of experiments it could be shown how the 

 quantity of pigment formation depends upon 

 the quantitative combination of the hered- 

 itary factors.^ The experiments were started 

 in 1909 with the purpose of working out the 

 genetics of melanism in moths. The experi- 



2 Froc. S. Soc. S. B., Vol. 89, 1915. 



3 Onslow 'g results are in the same line. 



