CORRESPONDENCE 303 



we imagine that the cytolysins act only by action on the germ-cells, it is 

 incomprehensible why these lysins, pumped into the veins of the mother 

 rabbit, are powerless to affect any of her germ-cells ripened after the preg- 

 nancy at which the injection takes place ; and he suggests the possibility 

 that the diminished and half atrophied lenses of the daughter rabbits are 

 producing lysins which affect their own germ-cells — and that is in essence 

 Lamarckism. 



8. Mr. Huxley states that Prof. Morgan has disproved my assumption 

 that the production of Mendelian mutants is due to irregularities of nuclear 

 division. This theory is, of course, not mine, but that of the leading British 

 Mendelian, Bateson ; it is the most plausible theory that has yet been put 

 forward, and it receives support from the cytological observations of Prof. 

 Gates on the mutants of GEnothera. It may be a mistaken hypothesis, but to 

 say that Prof. Morgan has disproved it is a pure piece of unmitigated bluff. 

 Neither Morgan nor any of his pupils has observed the genesis of a mutation, 

 nor is any of them in a position to say what kind of interchange may go on 

 between two chromosomes which meet in the meiotic pairing. May I, in 

 return for Mr. Huxley's kindness, direct his attention to some startling and 

 little-known experiments by Tornier on the development of the races of 

 gold-fish, in which he strives to show that the most gorgeous Mendelian 

 mutations, such as extravagantly elongated fins, forked tails, protruding 

 eyes, and colour variations including in their extreme range albinism, are one 

 and all due to the action in varying intensity of one pathological factor, 

 ■plasma weakness, itself due to the action of evil conditions on the earliest 

 stages of development. Many of Morgan's " mutants " will acquire a new 

 significance when viewed in the light of these facts, 



9. Lastly, Mr. Huxley graciously intimates that he merely wished to 

 relieve me from the trouble of overthrowing Weismann, since both Prof. 

 Morgan and he regard him as already overthrown, and Prof. Morgan can 

 do without him. Weismann has earned the gratitude of all biologists by 

 endeavouring to follow out to its bitter logical end the implication of a theory 

 which denies the inheritability of acquired characters — a task which Morgan 

 has not attempted. Morgan, who lives surrounded by experimental embryo- 

 logists happily unhampered by the provisions of an antiquated Anti- vivi- 

 section Act, is well aware that the assumptions of Weismann 's theory are 

 untenable ; but he is unable to put anything in their place. This is markedly 

 so in regard to regeneration ; it is all very well to dismiss in an airy fashion, 

 as Mr. Huxley does, the assumption that regeneration is due to " packets of 

 reserve determinants," and at the same time to af&rm the continuity of tho 

 germ-plasm (a conception hopelessly at variance with recent results of 

 experimental embryology) . Such an attitude on Mr. Huxley's part merely 

 proves that he is one of those " to whom to solve difficulties is easy, but to 

 feel difficulties is hard." 



Yours faithfully, 



E. W. MacBride. 

 July 21, 1921. 



To THE Editor of " Science Progress " 



THE GYROSCOPIC COMPASS 



From G. T. Bennett, Sc.D., F.R.S. 



Dear Sir, — ^A recent work with the above title has received unqualified 

 praise from your reviewer (see Science Progress, April 1921). Being pro- 

 fessedly non-mathematical, it may rightly escape any censure for such short- 

 comings as may be due to the exclusion of mathematical methods in dealing 



