THE FHOBLEM OF MITOGENETIC HAYS 



935 



Table 3. — Results with the Modified Geiger Counter 



{After Rajewsky, 224) 



1. Sender: onion root. Subjective counting with electrometer and loud-speaker. 

 Counting time, 5 min. 



2. Sender: onion plate pulp. Automatic registration. Counting time, 10 min. 



3. Sender: mouse carcinoma. Automatic registration. Counting time, 10 min. 



4. Sender: onion sole as in Gurwitsch's fundamental experiment. Automatic regis- 

 tration. Counting time, 9 min. 



same sensitivity. They placed the sender before one cell and the dif- 

 ference in the number of discharges between the two tubes indicates the 

 intensity of the radiation given up by the sender. 



In a lecture on the problem of mitogenetic rays, Gerlach (83) reported 

 the successful use of these modified Geiger counters in the detection of 

 mitogenetic radiation given up by blood. Unfortunately no details 

 concerning this work have as yet been published. Petri (241, 242) 

 published a simplified setup, the cell of which is so constructed that the 

 electrometer was combined with a photoelectric cell. The leaves of 

 the electrometer were charged and the speed of discharge was tested with 

 and without sender. The sensitivity reported for this instrument is not 



