262 



Dr. J. Joly. 



of water, which, after standing from a half to one hour, were introduced in 

 portions of 1 cm. 3 into four series of test-tubes containing 90mgrm. of maltose 

 dissolved in 4 cm. 3 of water. The concentration of the substrate in this 

 experiment is M/20, while the enzyme concentration varies between 2 x 10~ 4 

 and 20 x 10~ 4 grm. per cm. 3 . After 16 hours' incubation, the action was 

 stopped, and the quantity of maltose hydrolysed in each tube was determined 

 as before. The numbers obtained are set out in Table III. 



On plotting the percentage of maltose hydrolysed against the mean tem- 

 perature of the experiment the curves of fig. 2 are obtained. 



Here, again, each curve shows a maximum in the same region of temperature, 

 + 47°. Consequently, the optimum temperature of the enzyme is independent 

 of the enzyme concentration. 



Thus it is found, for the maltose of Aspergillus oryzce — as fqr the salicinase 

 of sweet almonds — that the optimum temperature of the ferment is indepen- 

 dent alike of the concentration of the substrate and of the concentration of 

 the enzyme. 



A Theory of the Action of Rays on Growing Cells. 

 By J. Joly, Sc.D., F.E.S. 



(Received May 28,— Read June 25, 1914.) 



The recent accessions to our knowledge of the nature of <y- and X-rays 

 bring the treatment, by these rays, of malignant and morbid growths, into 

 continuity with the treatment of lupus, etc., by the Finsen light or by other 

 actinic radiation. 



The pathological effects of the shorter and more penetrating waves have 

 been described by experienced observers as stimulative of the morbid growth 

 when the administered radiation is feeble in intensity and as inhibitive of 

 growth when the radiation is sufficiently intense. Here there is plainly an 

 effect produced by the short waves upon the growing cell, and the question 

 arises if from this and allied observations we cannot gain some insight into 

 the nature of the activity which characterises the malignant and morbid cell. 



The well ascertained facts of photo-electricity show that, in all cases, the 

 phenomena of direct light effects classed under that head are ascribable to the 

 expulsion of electrons as a result of the vibratory energy communicated from 

 the ether. The loss of electrons is attended by ionisation of the atomic or 

 molecular systems from which they are derived, the abstraction of the 



