22 



In the seed, I have been unable to demonstrate the 

 présence of an alcaloid either in the embryo, or in the en- 

 dosperm. The précipitâtes obtained by the aid of iodine 

 (fig. 154 Pl. XIX flg. 157, 160 Pl. XX) are due to the 

 présence of albuminous substances, as is shown by the 

 xanthoprotein- reaction (fig 162) 



Owing to the large quantifies of albuminous substances 

 here présent, small quantifies of alcaloid may have escaped 

 détection. 



As s )on as the cotylédons of the germinating seeds have 

 formed chlorophyll, they form alcaloid also (fig. 161 Pl. XX). 



f. Général remarks about the localisation of the alcaloid. 



The most important resuit of the investigation mentioned 

 above for physiological experiments to follow is the fact 

 that no alcaloid is found in the sieve- tubes, in other words 

 not in that tissue which preeminently serves to trans- 

 port the albuminous substances. On the contrary it is found 

 in the parenchyma, the tissue which is especially adapted to 

 the transportation of carbohydrates. It is also found in the 

 assimilatory tissue, while it is not présent as a reserve 

 substance in the seeds. 



The alcaloid is furthermore présent as the content of li ving 

 cells only, though in rare cases perhaps it is présent impreg- 

 nating the membranes of dead cells f. e. in the pith of the 

 stem, old woodfibres, old corkcells. But even if it be there; 

 which is by no means proved, tins is a secondary phenome- 

 nonarisenby thecellsapdiffusing towards the outside on the 

 death of the cell. In the bastfibres no al caloid is présent. 



Normally alcaloid is consequently présent exclus/' cel y <ts the 

 content of living parenchyma- cells or of other cells differing 

 but little from parenchyma. 



I believe that every parenchyma-cell may contain alca- 

 loid at some time or other exçept those which contain oxa- 



