40 PLANT PHYSIOLOGY 



by micro-organisms, the resulting ammonia then becoming available for the 

 higher plant (GERLACH, 1904 ; LOHNIS, 1905 ; FRANK, 1905). 



11. 34-5, for As we remarked . . . defective, read These are problems, how- 

 ever, to which as yet we can give only very imperfect answers. 



139, 1. 4, for Nevertheless . . . which have read Their solutions have 



1. 7, for This coagulation is permanent and read This coagulum is indeed 

 capable of swelling, but 



I. 47 P. 140, 1. 15, for Among the products . . . Pyridin group, read The 

 further decomposition of peptone results in the formation especially of amino- 

 acids, in addition to carbohydrates, ammonia, and humus substances. Many 

 of these amino-acids have been prepared in the pure state, and their constitu- 

 tion determined ; they have also been synthesized. The following summary 

 is taken from ABDERHALDEN'S Phys. Chem. p. 1160 : 



I. Aliphatic series : 



1. Monamino-acids : glycocoll, alanin, amino-isovalerianic acid, leucin, 



isoleucin : serin : aspartic acid, glutaminic acid. 



2. Diamino-acids : lysin, arginin. 



3. Sulphur-containing amino-acids : cystein, cystin. 

 II. Aromatic series : Phenylalanin, tyrosin. 



III. Heterocyclic compounds : pyrrolidin-carbonic acid (prolin), tryptophan, 

 oxyprolin. 



140, 11. 21-2, for The classification . . . constitution read In all probability 

 these amino-acids arise by hydrolytic decomposition without any profound 

 alteration of the proteid molecules. In other words, the proteid consists essen- 

 tially of a large number of linked amino-acids. The first step towards proteid 

 synthesis has been already accomplished (E. FISCHER, 1906), for it has been 

 found possible, by combining two to several amino-acids, to obtain so-called 

 polypeptids, that is to say, substances which are very closely allied to peptones. 



It will be the task of the future to arrange the proteids according to 

 their synthesis from different amino-acids. Meanwhile we must still content 

 ourselves with a provisional arrangement based on solubility, their capacity 

 for precipitation, &c. 



II. 38-9, delete III. Glutinoids . . . wanting. 



11. 48-56, for Let us now . . . nitric acid, read Let us now return to our main 

 problem, where and how nitric acid and ammonia are assimilated in green 

 plants. There is no doubt that the nitric acid is easily absorbed by the root 

 from the soil. The impermeability of the protoplasm to nitrates, which exhibits 

 itself when KNO 3 is used to effect plasmolysis, is at least only relative, and 

 does not come into play in solutions so dilute as those which are found in the 

 soil. It is often possible by using diphenylamin to follow the absorption and 

 migration of nitrates in the plant, but since many subsidiary circumstances 

 interfere with this reaction one can draw no conclusion from negative results. 

 In many plants the nitric acid absorbed rapidly disappears, because it obviously 

 very quickly undergoes alteration, but in other cases it is first of all accumu- 

 lated and then used up later, e.g. in the formation of the -fruit. 



141, 1. 2, for contain large read store up 



11. 6, 7, delete The nitrate . . . takes place. 



1. 13 P. 144, 1. 43, for Such storing of nitrate ... in the dark, read No 

 definite answer can as yet be given to the question as to where and under 

 what conditions further metabolism of nitric acid and the construction of 

 proteids take place, though, generally speaking, one is inclined to hold the 

 view that all plant cells may be capable of carrying out these processes. For 

 long it was thought that proteid synthesis took place only in the chloroplasts 



