THE EFFECT OF X-RAYS ON THE LENGTH OF LIFE 

 OF TRIBOLIUM CONFUSUM 



WHEELER P. DAVEY 



From the Research Laboratory, General Electric Company, Schenectady, New York 



FIVE FIGURES 



INTRODUCTION 



A great deal of work is reported in the literature on the effect 

 of X-rays on various forms of animal life. A study of this lit- 

 erature shows that, interesting though the results may be, it is 

 with few exceptions, difficult to duplicate the experiments be- 

 cause the physical data relating to the dosage have been so in- 

 completely given. Excluding work on human beings, the fol- 

 lowing work may be mentioned. 



Hastings, Beckton and Wedd^ found that the hatching of 

 silkworm eggs was accelerated by X-rays (dose not given) and 

 that the second generation was less fertile. Bordier^ X-rayed 

 six silkworms, giving them a dose of 7 to 8 H,^ at some unknown 

 penetration. He found an increased restlessness and smaller 

 size. The cocoon was only half size, and the moth did not emerge. 

 Hasebroeck^ was able to kill caterpillars of Charaxes (dose not 

 given), but those of Vanessa urticae after being X-rayed an 

 unknown amount developed into butterflies which were unable 



1 Hastings, Beckton and Wedd, Arch. Middlesex Hosp., 11th Cancer Report, 

 1912. 



2 Bordier, Le Radium, 2, p. 410, 1905. 



' Holzknecht units are measured by means of the change in color produced 

 by X-rays in a pastille of Barium Platino-cyanide. The reading of these pas- 

 tilles varies considerably with the wave-length of X-rays used so that the X-ray 

 measurements made by such pastilles are meaningless except when the voltage 

 across the tube is given, or when the 'penetration' of the rays is given in some 

 other reliable way. A better method of measuring X-rays is given later in this 

 article. 



■* Hasebroeck, Fortschr. a.d. Geb. der Roent., 11, p. 53. 



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