IRRADIATION OF LIVING PROTOPLASM 



641 



in vivo through a quartz tube. The migration velocity in the experiment 

 given changed from 12.4 ^i per sec. to 11.0 m per sec. after 13-^ hr. exposure 

 to the quartz mercury arc; the control remained practically constant. 



Recently Lisse and Tittsler (240) have considered the action of the 

 carbon arc (therapeutic B electrodes, 90 volts, 3 amp.) on the electro- 

 phoretic migration of cells of Escherichia coli suspended in water. They 

 used both the method of Northrop and Kunitz and that of Falk, with 

 some divergences in the results. When the Northrop-Kunitz chamber 

 was used for the cataphoretic measurements, the authors observed with 

 brief irradiation an increase in cataphoretic velocity; more severe treat- 

 ment caused a consequent decrease. The first effect is described as 

 "stimulating," the second as "lethal." One set of the results, in which 

 the electrophoretic measurements were made within 10 hr. after irradi- 

 ation, is reproduced from Table 10 of Lisse and Tittsler (see Table 3). 

 Uncorrected values are given because of the great possibilities of experi- 

 mental error in determining the correction factor from Smoluchowski's 

 equation. 



Table 3. — Effect of Carbon Arc on Migration Velocity of Escherichia coli 



(After Lisse and Tittsler, 200) 



Treatment 



Nonirradiated 



Irradiated 30 sec . . 

 Irradiated 1 min . . 

 Irradiated \]4, min 

 Irradiated 2 min. . 

 Irradiated 15 min. 

 Irradiated 30 min 

 Irradiated 60 min 



Number of 

 averaged 

 averages 



21 

 6 

 4 



2 

 6 

 8 

 9 



1 



Percentage 

 change 



+ 14.1 

 + 1.7 



- 0.6 



- 7.1 

 -34.8 

 -36.4 

 -49.5 



When the Falk capillary cell was used, other conditions being the 

 same, the "stimulation" effect could not be demonstrated for short- 

 irradiation treatments. There was a steady decrease in the charge. 

 Lisse and Tittsler point out that the increase observed in the pH of the 

 suspension might account to some extent for the change in migration 

 velocity. They also note that the time elapsing between irradiation 

 and the electrophoretic measurements is important but do not present 

 complete irradiation experiments in which this factor is controlled. 



There is evidence, therefore, from direct measurements of several 

 workers, that visible light and ultra-violet rays cause a decrease in the 

 surface charge of cells, bacteria in particular. There are no comparable 

 data concerning the effects of roentgen rays and radium, except the 

 recent report of Dozois, Tittsler, Lisse, and Davey (81). These workers 



