THE PROBLEM OF MITOGENETIC KAYS 



937 



is reflected, refracted, etc. These different features of this radiation are 

 especially well brought out by the work of Reiter and Gabor (231). 

 But it is somewhat difficult to understand these striking results if we 



1.10^ 

 1.10' 



1 



1.10'' 

 1.10-^ 



1.10'^ 



206210 2202^6 221 



254 



313 



2U'53l'340 365 



265270 280 

 rriAA 

 Fig. 4. — Graphic demonstration of the results using yeast as detector and mono- 

 chromatic light as sender. Outlined circles designate positive effects; half-blocked circles, 

 doubtful cases; blocked circles, zero effects. The ordinates express the intensities in 

 arbitrary units; the abscissas, wave-lengths in millimicrons. {After Chariton, Frank, and 

 Kannegiesser, 48.) 



accept the statement of Gurwitsch (HI) that the effect is not localized 

 on the detector and that it spreads several millimeters and then fades 

 slowly. The wave-length determined by Reiter and Gabor is around 

 X3400 A, a much higher value 

 than the estimates which 

 appear in the majority of 

 published papers, where the 

 wave-length is represented as 



o 



below 2500 A. An especially 

 extended investigation was 

 made by Chariton, Frank, and 

 Kannegiesser (48) (Fig. 4). It 

 is not possible to bring Reiter 

 and Gabor's estimate of X3400 



o 



A into any direct relation with 



the X1950 to 2500 A of the 



Gurwitsch school. It may well be that Reiter and Gabor had an entirely 



different effect. 



Does artificial radiation of the proper w^ave-length produce the same 

 effect? Frank (76), Reiter and Gabor (232), and Ruyssen (238) report 

 that this seems to be a fact. However, the energy necessary to produce 

 these effects from an artificial light source is of an entirely different order 



lY 



Fig. 5. — Arrangement for spectral analysis of 

 mitogenetic radiation. I, source of radiation, in 

 chamber with quartz window; II, rotating disk; 

 III, entrance slit of spectrograph; IV, agar blocks 

 with surface layer of yeast — blocks separated from 

 each other by celluloid strips. (After Gurwitsch, 

 108.) Newer experimental arrangements have a 

 very well adjusted exit slit. 



