SUPPLEMENT 55 



I. 47, after studied read (HEINRICHER, 1897 onwards). 



188, 11. 4-19, for HEINRICHER . . . such experiments read The meaning of 

 the parasitism in these plants has not as yet been fully explained. HEINRICHER 

 thought that they were completely independent in so far as carbon was con- 

 cerned, and that they took up minerals only from their hosts. His conclusion 

 was based on the abundance of nitrates in parasites, and on the demonstrable 

 decomposition of carbon -dioxide which took place in light. He has not, how- 

 ever, shown that this latter process is quantitatively sufficient, and yet this 

 is certainly necessary, after the very definite statements made by BONNIER 

 (1893) that the activity of the chlorophyll is only very slight. One cannot, 

 therefore, say with any certainty whether these plants, so far as carbon is 

 concerned, are autotrophic or whether they withdraw carbohydrate from 

 their hosts. SPERLICH (1902) postulates for them sometimes a greater, some- 

 times a less dependence on their hosts. There is a further possibility, viz. 

 that nitrogenous compounds such as proteids and amino-acids must be 

 taken up. 



II. 31-6, delete Exhaustive . . . PITRA (1861). 

 1. 49, delete when of no more use 



189, 11. 3-5, for in Fungi, and among ... no starch, read in Fungi. Among 

 nitrogenous reserves, proteids claim the first place ; they not infrequently 

 appear in a crystalline form ; further, volutin is very generally distributed 

 in lower plants, a substance which A. MEYER (1904) regards as a complex 

 body containing nitrogen and phosphorus. Among non-nitrogenous reserves 

 fats are especially frequent ; often, in addition, we meet with the alcohol 

 mannite, and trehalose a close ally of cane sugar. On the other hand, since 

 there are no chromatophores there is an entire absence in Fungi of the other- 

 wise so widely distributed starch. 



I. 22, after cell read (Kocn and HOSAEUS, 1894 ; comp. HEINZE, 1904). 



190, Lecture XVI is XV of the 2nd German Edition. 



1. 4 from bottom P. 191, 1. 9, for On examining . . . dry weight read 

 The increase in dry weight taking place in the course of the day in an assimilat- 

 ing leaf does not furnish us with a correct measure of the amount of assimila- 

 tion ; even if translocation of the assimilata from the leaf be prevented we 

 still find that the amount of assimilation is too small because part of the material 

 manufactured has, by evening, again become destroyed. Similarly with the 

 increase in dry weight exhibited by the plant during the course of its entire 

 vegetative period, all we have is the difference between the total amount 

 constructed in assimilation, and the total amount destroyed in dissimilation. 

 Under normal conditions, this difference is always on the plus side, i.e. in 

 spite of dissimilation there is always an increase in dry weight. It is, however, 

 by no means difficult to put the plant under conditions such that assimilation 

 ceases or is reduced (e. g. cultivating an autotrophic plant in darkness or depriv- 

 ing a heterotrophic plant of its culture medium) ; since, however, under such 

 circumstances dissimilation still goes on, the net result of growth now is a 

 diminution in dry weight. 



191, 1.33, for 3-38 read 3-88 



II. 39-40, for of a 0-003 . . . solution read of 0-003 to 0-03 per cent, solutions 

 11. 43-50, for The deficit . . . organic materials read Destruction of organic 



substance is remarkably common in organisms, and is carried out in a variety 

 of ways. Let us consider first that dissimilation process in the typical higher 

 plant which is known as respiration. By this we mean the production of 

 carbon-dioxide and water from organic materials. 



