318 THE CANADIAN NATURALIST. [Vol. ix. 



The Function of Chlorophyll. — One of the most import- 

 aot recent contributions to physiological botany, is contained in a 

 recent communication to the Berlin Academy of Sciences, by Dr. 

 Pringsheim, which appears to throw considerable fresh light on 

 the function of chlorophyll in the life of the plant. 



Having been led by previous researches to the conclusion that 

 important results might be obtained by the use of intense light, 

 he combined an apparatus by whicb the object under view should 

 be brightly and constantly illuminated by a strong lens and a 

 heliostat. If in this way an object containing chlorophyll — a 

 moss-leaf, fern-prothalium, chara, conferva, or thin section of a 

 leaf of a phanerogam — be observed, it is seen that great changes 

 are produced in a period varying from three to six or more 

 minutes. 



The first and most striking result is the complete decompo- 

 sition of the chlorophyll, so that in a few minutes the object 

 appears as if it had been lying for some days in strong alcohol. 

 Although however, the green color has disappeared, the corpuscles 

 retain their structure essentially unaltered. The change then 

 gradually extends to the other constituents of the cell ; the circul- 

 ation of the protoplasm is arrested ; the threads of protoplasm are 

 ruptured and the nucleus displaced ; the primordial utricle con- 

 tracts and becomes permeable to coloring matters ; the turgidity 

 of the cell ceases ; and the cell presents, in short, all the pheno- 

 mena of death. 



That these effects are not due to the action of the high tempera- 

 ture to which the cell is exposed under these circumstances is 

 shown by the fact that they are produced by all the difiFerent 

 parts of the visible spectrum. The result is the same whether 

 the light has previously passed through a red solution of iodine in 

 carbon bisulphide, through a blue ammoniacal solution of cupric 

 oxide, or through a green solution of cupric chloride. If the car- 

 bon disulphide solution of iodine be so concentrated that only 

 rays of a greater wave-length than 0.00061 mm. can pass through 

 it, these effects are not produced, although about eighty per cent, 

 of the heat of white sunlight is transmitted. On the other hand, 

 if the ammoniacal solution of cupric oxide be so concentrated 

 that the whole of the rays of a less wave-length than 0.00051 mm, 

 are absorbed, a rapid and powerful effect is produced, although 

 the amount of heat that passes is very small. It is thus seen that 

 the phenomena in question are not the result of heat. 



