46 PLANT PHYSIOLOGY 



I. 55, for Such celluloses . . . giving read In seeds especially we find certain 

 celluloses deposited, which give 



158, 11. 1-2, for on treatment . . . dilute, read on treatment with acids ; in 

 quite dilute acids they are hydrolysable. 



II. 25-32, for The distribution . . . activity.] read Thatcytases are widely 

 distributed is obvious (HERISSEY, 1903) ; they occur wherever hemicelluloses 

 have to be dissolved. It is true that they often occur in very small quantities, 

 and the slow dissolution, e.g. of the endosperm of palm seeds, may be thus 

 explained. Owing to the fact that the products of hydrolysis, mannose and 

 galactose, are usually not found in plants, it is very probable that they are 

 rapidly altered and used up. 



I. 42, after starch read ; BEIJERINCK (1904) also regards oil as a product 

 of assimilation in Diatoms. 



160, 1. 4, for are always read become gradually 



II. 48-53, for the amido-compounds . . . 1905) read the amino-acids. 



161, 11. 18-44, f or [These have also . . . does not say] read In all probability 

 there are several kinds of trypsin, each with its own specific mode of action 

 (PoLLAK, 1904). One difference between vegetable and pancreatic trypsin is 

 that it operates best in an acid solution. Recently, the occurrence of erepsin 

 in plants, and especially in seeds, has been affirmed (VINES, 1905, 1906 ; DEAN, 

 1900). This enzyme can act only on albumoses and peptones (not on proteid), 

 breaking them down rapidly into amino-acids. Although it has not been 

 possible hitherto to prove the general presence of proteolytic enzymes in seeds, 

 it must not be concluded that they are absent ; but since in individual cases 

 only peptones and proteid can be obtained from seedlings which empty them- 

 selves of their own accord (PuRiEwrrscH, 1897), one must assume that hydro- 

 lysis of proteid is not always necessary in germination, and that proteid as 

 such can also migrate through protoplasm and cell-wall, a possibility on 

 which we have not hitherto reckoned, but which may be regarded as not 

 improbable, more especially in view of the power which fats possess of passing 

 through these walls. 



From what has been already said, compounds of sulphur and phosphorus 

 are set free by proteolysis during germination. Primary sulphur-containing 

 products, such as cystin, cystein, &c., have not as yet been found in plants. 

 Sulphates appear in their place, but how they arise is not known. The mode 

 of origin of the phosphoric acid that appears in germination (!WANOFF, 1902) 

 is also but imperfectly understood ; many albumins and proteids, and perhaps 

 also lecithins, may take part in its formation. According to recent views 

 (CZAPEK, 1907, p. 497), the lecithins and cholesterins are constructive units 

 of the protoplasm, and not reserves, and hence no breaking down of these 

 occurs in germination. Phytin finally may be regarded as a chief source of 

 phosphorus, a body which plays an essential part in the formation of aleurone 

 grains (POSTERNAK, 1903). Lastly, the aleurone grains contain a quantity of 

 other ash constituents of special value to the plant (POSTERNAK, 1905), for the 

 most part in organic combination ; in germination all these bodies are set 

 free as inorganic salts. 



161. With the last paragraph a new lecture begins in the German edition with 

 title 



THE UTILIZATION OF THE PRODUCTS OF ASSIMILATION. II 



OTHER STOREHOUSES OF RESERVES. TRANSLOCATION AND FATE OF THE 



DISSOLVED RESERVES 



