50 



produced by other causes tliau by the abseiKje of iron, as has been 

 already pointed out (j). 15). Raumer ascribed to magnesia and not to 

 lime, as Boehm has done, the transportation of starch, basing his claim 

 on the ground that in the beginning the leaves contain not only con- 

 siderable starch, but also a relatively large proportion of magnesia, 

 whicli condition is found later in the stems. Finally, magnesia is found 

 to be increased in the seeds, in which starch also is generally deposited. 

 This hypothesis does not, however, seem to be well founded, since the 

 relations indicated are not direct. Many other facts make it much more 

 ]^rol)able that it is the proteids and not the starch that have a close rela- 

 tion to magnesia. Where development is going ou, starch is required 

 for furnishing the necessary carbon and hydrogen in the production of 

 proteids, hence magnesia is found in cases where the starch is migrat- 

 ing. Here magnesia is connected with the protein production and not 

 witl*- the migration of starch. Furthermore, the organoids of starch 

 formation, the plastids, also require magnesium salts for their growth 

 and multiplication, since they contain phosphoric acid in their nucleo- 

 proteids; hence there also exist some reasons for the belief in the 

 remote connections between the starch content of an organ and the 

 amount of magnesia present, but not in the direct connection supposed 

 by llaumer. 



INCREASE OF MAGNESIA IN OILY SEEDS. 



If the writer's theory as regards the relation of magnesia to i)hos- 

 phoric acid is correct, more magnesia ought to be found where both 

 compounds, uucleo- proteids as well as lecithin, are formed than where 

 nucleo-proteids alone exist, since the assimilation of phosphoric acid is 

 required not only for the formation of nucleo-proteids, such as chroma- 

 tin and plastin, but also for that of lecithin. Lecithin is a constant 

 concomitant of fat, and therefore seeds rich in fat ought to contain, 

 cei. par.^ more magnesia than such as are rich in starch. A review of 

 Wolff's ash tables confirms this deduction. The following table shows 

 that for 1,000 parts of organized substance there are of magnesia in — 



starchy seeds. 



Oats .. 

 Barley 

 Eye... 

 Maize . 



Per cent. 

 1.9 

 2 

 2 



i.9 



Oily seeds. 



Cotton 

 Flax . - 

 Poppy 

 Kape.. 



Per cent. 

 5.6 

 4.7 

 4.9 

 4.6 



The average proportion of magnesia in starchy seeds to that in oily 

 seeds, therefore, is as 2 to 5. 



It may furthermore be pointed out that fungi grown in culture solu- 

 tions containing only traces of magnesia form no spores. Spores, how- 

 ever, contain lecithin, and in all probability relatively large amounts of 

 nucleo-protein. Here the importance of magnesia can be readily dem- 

 onstrated by increasing its amount in the culture solution, after which 



