1867.] Botany and Vegetable Physiology. 391 



tains that Chlorophyll (or some closely-allied modification thereof) 

 is contained in all growing plants, as the principal actor in the pro- 

 cess of assimilation, acting perhaps in a manner analogous to that 

 which the oxygen-carrying constituents of Hood exhibit in animals. 

 Dr. Colin has also recently shown elsewhere that the presence or 

 absence of Chlorophyll in the lowest forms of Plants and Animals 

 has a very important bearing on then' direction of motion. They 

 always move towards the light, and if variously coloured light be 

 used, towards the highly refractive actinic rays in preference to the 

 thermal red ones. 



Dr. Cohn believes that the decomposition of carbonic acid and 

 the evolution of oxygen through the Chlorophyll, under the influ- 

 ence of light, offer a fair explanation of some of the movements of 

 these minute coloured organisms. 



A fragment of chalk coated over one half with a resinous 

 cement and placed in dilute acid is projected with the coated 

 surface foremost, by the evolution of carbonic acid from the ex- 

 posed extremity. In a similar manner, Dr. Cohn supposes that the 

 chemical action induced by the action of light on the chlorophyll 

 aggregated at one part of such bodies, as the Oscillarise or Euglenm 

 may give rise to those axial rotations which frequently become apparent 

 as longitudinal motion. Dr. Cohn also mentions certain Oscillarise, 

 namely, the genus Beggiatoa, which, probably by the decomposition 

 of sulphates, develop free hydrogen-sulphide in the water in which 

 they thrive. Since this group of algae alone can flourish in hot and 

 strongly saline solutions, he suggests that it is probable that the 

 first organisms which were present in the primordial sea which 

 covered the earth, and was of very high temperature, if we may 

 reason upon the inductions of geologists, were Oscillarise or rather 

 Chroococcacese. 



The Situation of the Alkaloids in the Bark of the Cinchonas. — 

 Any facts relating to the sources or supply of Quinine must have 

 considerable interest. Some years since M. Wigand tried to 

 demonstrate that the alkaloids of the Cinchonas are developed in 

 the liber. He observed that thin sections of the bark soaked 

 in cochineal became stained more strongly in that layer which 

 is known as liber, than in that part of the bark called paren- 

 chyma; and from this he concluded that quinine was more 

 abundantly present in the liber than in the parenchyma, acting as a 

 mordant. M. Carl Miiller, having failed to confirm M. Wigand's 

 observations, has adopted a different method of examination. He 

 by a very ingenious process separates the liber and parenchyma, 

 and then analyses the two separately. He finds that the parenchyma 

 contains9-876 per cent, of quinine, whilst the liber only contains 2*462 

 per cent. It appears also that the quinine is the more abundant in 

 proportion as the bark is more developed, which would lead one to 



