39 
It is not felt that this conclusion can be stated with certainty 
from a consideration of the above ash analyses alone. If the chlo- 
rosis is caused by the combined effect of an excess of lime and a lack 
of iron in the plant, it would seem that there should be a definite 
ratio of lime to iron in the ash which would induce the chlorosis. 
But in the above analyses no such ratio is apparent. 
It is felt that analyses of other species of plants that become 
chlorotic on calcareous soils are needed for confirmation, and this 
work is now in progress. 
The lower content of nitrogen in the chlorotic plants is probably 
not the cause of the chlorosis but the result., The absorption of 
nitrogen can hardly be interfered with in calcareous soils, and in all 
the experiments the plants received a liberal supply of easily assimi- 
lable nitrogen. Similarly it appears that the lower content of potash 
found in some of the chlorotic plants of the table on page 35 is but 
the result of the chlorotic condition. In this table it will be seen 
that some chlorotic plants contain 38 per cent, 48 per cent, and 55 
per cent of potash in the ash, quantities much greater than many 
healthy plants contain. These analyses would tend to contradict 
the view held by Sorauer' and some others that the chlorosis on 
calcareous soils is caused by a lack of available potash. 
ENZYMS IN CHLOROTIC AND GREEN LEAVES. 
Woods has shown? that under certain pathological conditions of 
various plants, as in the mosaic disease of the tobacco, the attendant 
chlorosis seems to be caused by the presence of an excessive amount 
of the oxidizing enzyms, oxidases and peroxidases, in the leaves. 
Tests were made to see whether in the chlorosis of the pineapples the 
phenomenon was accompanied or caused by a like increase in the 
enzyms. For this purpose the content of normal green leaves in 
oxidases and peroxidases was compared with that of chlorotic leaves. 
The method employed in comparing the different amounts of 
enzyms was as follows: In every case equal quantities (generally 10 
grams) of the fresh leaves were triturated with sand and chloroform 
water ina porcelain mortar. The solution and macerated leaves were 
then made to 500 cubic centimeters with distilled water, allowed to 
stand 15 hours, and passed through a dry filter. The filtrate was 
used in making the comparative tests; 1, 2, 4, 6, 8, and 10 centi- 
meters of these solutions were put in Nessler tubes, the volume of 
each tube made to 10 cubic centimeters with distilled water and equal 
quantities of neutralized hydrogen peroxid and freshly prepared 
2 per cent alcoholic solution of guaiacum resin added to each tube. 
At the end of 10, 15, or 20 minutes the various tubes were compared 

1 Loc. cit. 2A.F. Woods. Centbl. Bakt. [etc.], 2. Abt., 5 (1899), No. 22, pp. 745-754. 
[Bull. 11] 
