790 SCIENCE PROGRESS 



to the sterility of hybrids leads to similar negative conclusions, and the best hope 

 that Mr. Bateson has to bring us is the expression of his conviction that the 

 prospect of permanent progress is greater if science retreats from the speculative 

 position which he thinks it has occupied. He states his belief that new light will 

 most probably come from the pursuit of genetic research. Those who think that 

 a little speculation is the salt of experimental work, can at least comfort themselves 

 with the reflection that there seems no dissociation of any radical nature between 



speculation and genetic research on Mendelian lines. 



P. C. M. 



A Possible Physical Aspect of the Trichromatic Vision Theory. By C. 



Timiriazeff, F.M.R.S. [Pp. 12.] (Moscow, 1913.) 



This pamphlet is an ingenious attempt to associate Edridge-Green's Theory of 

 Vision with the Trichromatic Theory. The author suggests that the distribution 

 of the red sensation corresponds to the perception of amplitudes of the vibrations 

 that the green sensation curve corresponds to the absorption curve of the visual 

 purple, having its maximum in the green, and sloping to the limits of the spectrum: 

 the third curve having its maximum in the violet is attributed to the perception 

 of the oscillation frequencies. It is difficult to suppose that the sensation of red 

 can be only caused by the perception of amplitude any more than a treble note 

 should become a bass one when struck very violently. The author in support of 

 this view alludes to the decrease of the red sensation with the decrease of the 

 intensity of light, and the converse effect. This pamphlet will be interesting to 

 those who incline to the Trichromatic Theory, but to those who claim that the 

 Trichromatic Theory is quite untenable, and that the objections to it have never 

 been answered, it will only be regarded as an ingenious speculation. So many 

 of the so-called facts of colour-vision are merely speculations based upon the 

 theory, and do not bear any relation to the actual facts. The terms red-blindness 

 and green-blindness convey no meaning to us, as different varieties are classed 

 under the same heading. A theory of colour-vision should be able to account 

 for the facts as given, for instance, in Professor Starling's Text-book of 

 Physiology. 



Irritability. A physiological analysis of the general effect of stimuli in living 

 substance. The Silliman Lectures delivered at Yale University in 1911-12. 

 By Max Verworn, M.D., Ph.D., Professor at Bonn Physiological Institute. 

 With Diagrams and Illustrations. [Pp. xii + 264.] (New Haven: Yale 

 University Press. London : Henry Frowde, Oxford University Press, 

 1913. Price 15^. net.) 



Prof. Max Verworn is no mean successor to those who have preceded him in 

 the Silliman lectureship, the names of whom include Sir J. J. Thomson, Professors 

 Sherrington, Bateson, and Svante Avrhenius. The present volume will add to the 

 very high reputation which Prof. Verworn already enjoys both as an investigator 

 and writer. The subject which forms the title of the lecture deals with a property 

 of the living substance which is perhaps its most fundamental characteristic, and 

 the author has made it peculiarly his own, for the volume deals with his researches 

 which have covered a period of twenty years. 



Those acquainted with Verworn's General Physiology will know that the author 

 was one of the earliest to recognise the importance of a study of the subject from 

 the comparative standpoint ; the muscle-nerve preparation from the frog's leg is 



