102 GOODSPEED—FIELD SURROUNDING CROOKES TUBE. . [May 15, 
Sagnac rays emanating from his hand, the visible fluorescence gen- 
erated by the tube was not cut off by any opaque screen, and there 
is no reason for assuming that this light may not have played some 
part in his results. In the present experiments everything has been 
done in complete optical darkness. 
I have been unable to find out if Guilloz’s pictures were actually 
published, and so cannot compare his results in detail with my own. 
In connection with the present subject, my attention has been 
called by unpleasant personal experience to a very suggestive coin- 
cidence. The nature and pathology of X-ray dermatitis is, and has 
been from the first, surrounded with mystery. Much ‘ingenious 
technical literature has been published in the medical journals all 
over the world for the last six years, with the result that to-day 
little is known about either the real cause, the nature, the proper 
method of preventing, or the best treatment of this most distressing 
and lingering affliction. A comparative history of many cases 
reveals many inconsistencies, followed by an increased sense of 
ignorance on the subject. The personal experience to which I 
~ refer suggests a possible step towards a better understanding of the 
phenomenon. 
During a week in June, 1902, I occupied the Roentgen ray room 
asasleeping apartment. At the end of this time an acute inflamma- 
tion of the eyes and throat appeared, all symptoms of an ordinary 
cold or of any digestive disturbance being absent. At the end of 
the week referred to I left town and the inflammation gradually 
subsided during the next three or four days. For similar reasons I 
had occasion to sleep in the same room during the first week of the 
present month. At the end of that time my attention was pain- 
fully called to a.recurrence of the symptoms observed a year ago. 
On ceasing to sleep in the room all trouble disappeared. 
As I have never had any such experiences other than those referred 
to, it seems not too much to infer that the peculiar inflammatory con- 
dition may have been due to some action of the secondary emana- 
tions sent out by the walls and air of the room after the generation 
of X-rays had ceased. Continuous breathing of such ‘‘ darkly 
phosphorescing ’’ air might well account for the trouble in the 
throat and vocal chords. In the daytime the doors and windows 
were always more or less open, so that the air was continuously 
changing, and my eyes were protected considerably by glasses, 
through which neither the primary nor the secondary rays pass 
easily. 
