EFFECT OF CERTAIN SOLIDS UPON THE GROWTH OF 
SEEDLINGS IN WATER CULTURES.' 
J. F. BREAZEALE. 
(WITH FOUR FIGURES) 
In certain investigations on the growth of wheat seedlings in 
aqueous extracts of soil, it was observed that the growth of these 
plants was greatly accelerated by the presence in the medium of | 
undissolved calcium carbonate. That the observed acceleration was 
not due to an increase in dissolved calcium was apparent from the 
fact that the presence of other slightly soluble salts of this element 
failed to produce any response. It appeared possible that the effect 
of calcium carbonate might be due to its taking up some injurious 
substance present in the extract. This was suggested by NAGELI’s 
well-known discovery? that water, which is toxic to algae because of 
minute traces of metals, can be improved by placing in it such insoluble 
bodies as graphite, paraffin shavings, or torn filter paper. It was 
determined to try other slightly soluble compounds which might 
remove from solution small amounts of solutes, either by chemical 
action or mechanically. The results of this investigation make up 
the present paper. 
The Russian variety of wheat known as “Chul,” obtained from 
Arizona, was used in most of these experiments. The seedlings were 
germinated in sand and then grown in water cultures in large-mouthed 
black bottles of about 60°° capacity. They were fixed in cork stop- 
pers, four in a bottle, in the manner described by WHITNEY and 
CaMERON: for cultures of this kind, so that the roots were submerged 
in the solution while the seeds were just above its surface. The 
solutions were always aerated by violent and repeated shaking before 
the cultures were started. During the growth of the plants the bottles 
were weighed in groups of three at intervals of three or four days, 
and the water lost was replaced with distilled water. The manner 
I Published by permission of the Secretary of Agricu 
2 Nageli, C. von, Ueber ip SPL E Sitar ees in lebenden Zellen. 
Denkschr. Schweiz - Naturforsch. segs 33:2: 
3 Wuitney, M., and Cameron, F. K. geese in soil fertility. U. S. Dept 
Agric., fina of Seite Bull. sa sand 
Botanical Gazette, vol. 41] : [54 
