46 



by bipartition in vsuch simple alga forms as Protococc^is, Stichococcus, 

 and Palmella, but these chloroplasts appear to be of a lower order tban 

 those of Cladophora, Zygnema, or Spirogyra. 



The nutrition of the chloroplasts is in all probability cared for by the 

 nucleus, hence it is reasonable to suppose that nuclei which prepare 

 calcium-protein compounds for themselves furnish these same com- 

 pounds to the chloroplasts also. This is probably the simplest expla- 

 nation as to why chloroplasts become sensitive to even neutral oxalates 

 in all plants the nuclei of which are killed by oxalates. Where the nuclei 

 contain calcium-protein compounds the chloroplasts also contain them. 



The writer has advanced the view that a higher development in form 

 and function becomes possible only when the lower forms of life acquire 

 the ability to assimilate lime and to utilize the resulting calcium proteid 

 compound for organization purposes. This seems to him the simplest 

 explanation of the fact that lime salts are required by all plants except 

 the very lowest forms. Agreeing es]iecially well with this view is the 

 further observation that neither neutral oxalates, nor magnesium, nor 

 strontium salts are injurious to these lowest forms,^ although noxious 

 to all other plant life. 



If lime were necessary only for certain processes of metabolism in 

 plants, as some authors claim, it would not only follow that tlie higher 

 forms of algie have quite a different mode of metabolism from the lower 

 ones, but it would also remain entirely incomprehensible why mag- 

 nesium salts act so poisonously on the nucleus and why only calcium 

 salts can prevent this deleterious effect. It would be very interesting 

 to know the exact line of development below which calcium salts are 

 not re(iuired and above which they are indispensable for plant life. 

 A division of the algte into two such groups would certainly prove 

 instructive. 



ON POSSIBLE RELATIONS BETWEEN THE LIME AND THE TRANSPOR- 

 TATION OF STARCH. 



One of the tirst disturbances to appear when there is a deficiency of 

 lime is the cessation of starch transportation. Starch gradually accu- 

 mulates in the lower parts of the stem, and even its transportation 

 from the storage receptacles to the axial parts may gradually stop. It 

 has already been seen (p. 18) that a similar phenomenon was observed 

 by Nobbe in plants showing a deficiency of chlorine compounds. Two 

 causes, either separately or combined, may produce this phenomenon, 

 and it follows, therefore, that the conditions bringing it on in different 

 cases may not necessarily be wholly identical. One cause may be 

 that cells fail to produce the diastase which is necessary for dissolving 



^Palmella can develop quite well, even in 4 per cent solutions of neutral potassium 

 oxalate or magnesiiim sulphate to which traces of ammonium sulphate aud potassium 

 phosphate ha-l been added. Beer yeast may be kept for several hours at 30° C. in a 

 1 per cent solution of magnesium nitrate without serious injury. 



