28 PLANT PHYSIOLOGY 



apparently, a just one, of the accuracy of this method and a description of 

 a better form of apparatus are given by POLLACCI, 1905 a.) 



1. 22, after is produced read Thus BONNIER and MANGIN (1886) found 



the fraction -- = i-o8 in ivy, and 1-06 in the horse-chestnut and Syringa ; 



so that, as a matter of fact, somewhat more oxygen is given off than corre- 

 sponds to the carbon-dioxide decomposed. This excess of oxygen, for reasons 

 which will be given later (Lecture XVI), may be considerably greater in certain 

 plants. Whether, in addition to oxygen, other gases also, e.g. hydrogen (PoL- 

 LACCI, 1905 b), make their appearance during carbon-dioxide assimilation is as 

 yet very doubtful. 



11. 40-1, for Another . . . has been more often, employed read MOLISCH 

 (1904) has carried out elaborate investigations with the aid of this method. 

 Yet another physiological method has been very often employed, 



106, 1. 30, after number read exclusively ; after colour read only 



I. 44 P. 107, 1. 2. for Recently EWART . . . quite inactive read It has 

 been recently repeatedly stated that pure yellow etiolated chloroplasts can 

 also decompose carbon-dioxide (ENGELMANN, 1881; EWART, 1897; KOHL, 

 1906). MOLISCH, however (1906), using the very sensitive luminous bacterium 

 method, was unable to demonstrate any evolution of oxygen from such 

 chloroplasts. 



107, 11. 11-14, delete [MOLISCH'S . . . dead cells.] 



II. 20-1, for The dependence . . . assimilation, read Further, MOLISCH 

 (1904) has, with the aid of the luminous bacterium method, observed carbon- 

 dioxide assimilation in chloroplasts taken from dry dead leaves (compare 

 BALDASSERONI, 1906). 



11. 35-8, for in the chloroplasts, and . . . Fig. 24 read in the chloroplasts. 

 According to MOLISCH (1906) this is due to the fact that certain parts of the 

 cell act as cloudy media, and obscure the fluorescence. The spectrum of crude 

 chlorophyll is shown at the top of Fig. 24. 



108, 1. i, for six read seven 



11. 2 and 5, for three read four 



11. 6-8, for The figure . . . product of it read The fourth band, just in front 

 of line E, probably belongs not to chlorophyll itself but to a decomposition 

 product of it. 



1. 12, for dense read denser 



1. 32 P. 109, 1. 10, for Great progress . . . This substance read Consider- 

 able progress has been made of recent years in the chemical investigation 

 of true chlorophyll (compare MARCHLEWSKI, 1901 ; CZAPEK, Biochemie, 

 I, p. 449). We know that it is an exceedingly complex organic body, contain- 

 ing, in addition to H, O, N, and C, magnesium in relatively large quantity 

 (WILLSTATTER, 1906). Iron, on the other hand, as already mentioned, is 

 absent from the chlorophyll molecule, and even phosphorus is only doubtfully 

 present. On this latter ground it was held until recently that chlorophyll 

 must be regarded as a lecithin compound, but WILLSTATTER (1906) has shown 

 that this view is incorrect. It would appear that we have here to deal with 

 an albuminous or proteid body, and, as generally in these cases, we must 

 look to detailed researches into the decomposition products of the substance 

 to furnish us with an insight into the complex structure of its molecule. Such 

 decomposition products are obtained, by the action of acids and alkalis, in 

 quantity, and have received names very few of them can, however, be simple 



