135 



The gradual (raiisformation of solutions of odorous substances 

 beginning with the formation of aniicrons, that develop into sub- 

 microns, ap|)ears to be largely inlluenced by light. When kept in 

 the dark, the process is slow in aqueous solutions. There are even 

 several substances, e.g. chinolin, in which it does not appear at all, 

 but in which it comes forth distinctly in daylight. It should also be 

 observed that the effect of ultra-violet light is much stronger than 

 that of daylight '). 



When exposing a eugenol-solution in a quartz test-tube at Ys ™- 

 distance from the light of a mercury quai't/ lamp, opalescence is 

 attained within half an hour, which otherwise is not arrived at in 

 a fortnight. An electric arc-lamp has the same effect in a smaller 

 degree. This quickening of transformation does not occur when the 

 quartz-tube is enclosed in stanniol-paper. The same was observed 

 with all other solutions. Even a heliotropin solution, ulti-amicroscopically 

 empty, shows, after half an hour's radiation, numerous micellae. 



Besides by the ordinary light-waves and the ultra violet rays, 

 odorous substances can also be rendered colloidal by radiation with 

 radium kept in vitro. In order to ascertain this we took two perfectly 

 equal glass cuvettes with parallel walls, each tilled with saturated 

 odorous solution. In one of the cuvettes a closed glass tube was 

 inserted, in which 200 mgrs of a mixture of radium- and barium- 

 bromide containing 0,18 7o RaBr'. If the experiment was performed 

 with a saturated heliotropin solution, the control fluid remained 

 ultramicroscopically empty, whereas the sohitiou, in contact with 

 the radium tube, showed in 24 hours a base of amicrons and 10 

 submicrons per microscopic field. Something similar occurred in a 

 short time also with the other odorous solutions of the table, though 

 with every following substance of the series more lime was required 

 to obtain a difference in dispersity between the radium-cuvette and 

 the control-cuvette. 



Not only the admitted electro-magnetic waves of the visible light, 

 the ultraviolet light and the y-rays of the radium, but also the 

 mechanical energy is competent to give to a fresh-prepared, saturated 

 multitomic odorous solution the energy needed for an amount of 

 surface-energy sufficient for the formation of numberless amicrons 

 and submicrons, to be observed in the gradually developed suspensoid. 

 By sliaking the fluid forcibly, transformation is largely promoted. In 



1^ Besides opalescence also nuorescence is generated. We aic unaJjle to decide 

 whether there is any relation l)et\veen light electricity and the ol)served highly 

 accelerated transformation to a colloidal state. Gf. Hellwachs on Lighl-eiectricily 

 in Marx's Hab. d. Radiol. Vol. Ill p. 438. 



