50 PLANT PHYSIOLOGY 



under any conditions ammonia must be split off, and from it first of all amides 

 must be constructed. The formation of these bodies would thus be synthetic, 

 and in the process probably some carbohydrate or other must take part. 

 We ought to note in this relation the discovery by SCHULZE and WINTERSTEIN 

 (comp. SCHULZE, 1906), that in Ricinus, monamino-acids, otherwise so common, 

 do not make their appearance during germination. In place of them there 

 occurs a body which bears the name of ricinin, and which possesses a 

 pyridin group. Doubtless, it arises from primary or secondary decomposi- 

 tion products of proteid. It is probable that we have here a key to the inter- 

 pretation of alkaloids, many of which also are characterized by the possession 

 of a pyridin group. Alkaloids with other constituent groups also must be 

 derived from products of proteid splitting. No accumulation of asparagin 

 takes place in light, first because carbohydrate is under these circumstances 

 abundant (PFEFFER, 1893), and also because light is directly favourable to the 

 construction of proteid (BALICKA-!WANOWSKA, 1903 ; GODLEWSKI, 1903). 



175, 11. 36-52, for It must be noted ... of diastase, read Fat also appears ; 

 often at least in our native trees during winter, while starch disappears. The 

 close connexion which one was led to assume between these two processes 

 as a result of FISCHER'S (1890) work does not appear to exist (NiKLEWSKi, 

 1905 ; comp. also FABRICIUS, 1905). Where the fat comes from is not clear ; 

 on the other hand, it has been shown that the starch which disappears becomes 

 transformed into sugar, and its accumulation is a direct result of low tempera- 

 ture. According to LECLERC (1904), fairly abundant accumulations of hemi- 

 celluloses arise during the winter as thickenings on the cell-walls. Conversely, 

 it is possible at any time during the winter to induce a formation of starch 

 by bringing amputated twigs into a warm room. A similar phenomenon has 

 long been known in the ' sweetening ' of potatoes at temperatures just above 

 o C. (MuLLER-TnuRGAU, 1882). The meaning of this starch-formation may 

 perhaps be found in the lowering of the freezing-point, but the cause of it is 

 as yet quite unknown ; at all events it cannot be referred to the peculiarities 

 of the diastase. It is as yet impossible to say how far our conceptions as to 

 fat-formation in seeds and its relation to carbohydrates must be modified as 

 a result of the observations of NIKLEWSKI on trees. 



In addition to the storehouses of reserve mentioned we also find far- 

 reaching transformations taking place in the materials stored in fruits, but 

 into them we cannot enter (comp. e.g. GERBER, 1896 ; LECLERC, 1905). 



176, 11. 20-2, delete [Many . . . (1904).] 



11. 31-41, delete We may at least . . . Naturw. 22). 



177, Lecture XV is XIV of the 2nd German Edition. 



Ill, title, read METABOLISM OF HETEROTROPHIC PLANTS 



11. 26-7, for chlorophyll, all ... have seen that read chlorophyll, while 



I. 29, after substances read and hence are heterotrophic. 



II. 31-44, for exclusively out of carbohydrates . . . adding sugar.] read 

 exclusively out of assimilata formed by neighbouring leaves (Josx, 1895). 

 By the artificial addition of organic compounds it has hitherto been possible 

 only to a limited extent to induce growth in higher plants in darkness (LAURENT, 

 1903 ; LEFEVRE, 1906). How that comes about we do not know. Lower 

 plants, e.g. certain Algae, according to ARTARI (1904) and PAMPALONI (1905), 

 even if they be adapted to the employment of carbon-dioxide, can frequently 

 still grow perfectly well in the dark at the expense of glucose and peptone (or 

 some other source of nitrogen). Indeed, many of these forms (Euglena, ZUM- 

 STEIN, 1899; Chlorella variegata, BEIJERINCK, 1904, &c.) range themselves 



