JoLY — Radio-TJierapi/ : its Scientific Basis and its Teaching. 507 



These facts suggest that tlie antagonistic action of the acid and tlie alkali 

 in the cell is parallel witli the antagonistic action of restrainer and sensitizer 

 upon the film. The latter may be illustrated by a simple experiment on the 

 film. A latent image is formed on a dry plate, either by brief exposure to 

 liglit or by application of a sensitizer — such as nicotine, gallic acid, or pyro- 

 gallic acid. The application of a wash of very dilute HCl left on the plate 

 for a couple of minutes will tlien obliterate the latent image, as will be found 

 upon applying a developer. The effect is best obtained with highly dilute 

 acid. Such a strength as is said to prevail normally in the secretion of the 

 stomach — 0-2 to 0-4 per cent.- — works effectively. 



The possibility that substances which act as sensitizers or restrainers 

 on the film may act to promote or retard mitosis in the cell must be 

 admitted from these results, some of which are obtained by direct experi- 

 ment on the living cell. 



The fact that cancer of tongue, lip, and throat, and generally of parts 

 around the mouth, is chiefly confined to the male sex has before now been 

 regarded as raising a suspicion as to the injurious effects of tobacco 

 smoking.' 



The effects of a solution of the volatile substances evolved from burnt 

 tobacco, upon the film, support this inference. If tobacco smoke is bubbled 

 through water, and a little of this water is poured on the photographic plate 

 in the dark, and again washed off, a vigorous latent image will be obtained, 

 as development will demonstrate. 



At the time of communicating the subject-matter of this paper to the 

 Dublin Clinical Club I treated this matter as a purely extrapolatory 

 suggestion. I was not then aware of the fact that C. and R. Hertwig 

 and Galleotti' mention nicotine as one of a few substances which they 

 found, by direct observation on animal cells, produced pathological mitosis 



' statistics of cases treated in the Middlesex Hospital in 1913 show that the numbers of cases 

 of the kind in the male and female sexes stand as 8'3 ; 1. Thus : — 



Tongue, 37 : 3 



Lips, 13 : 



Larynx, . . . . . 13 : 2 



Pharynx, 1:3 



Palate, 8:0 



Floor of Mouth 6:1 



Tonsils, . . . . .5:1 



83 10 

 Archives xxxiii, p. 2. 

 - Eeferied to by Moore, Eoaf, and Whitley : Proc. Roy. Soc, Ser. B, yol. Ixxvii, Oct., 1905. 



SCIENT. PKOC. R.D.S., VOL. XIV., NO. XXXVII. 4l 



