11 
integrated cell contents of the spongy parenchyma. The amount 
of starch which is stored up in the stem of the pineapple, however, 
is still almost, as gre^t in plants growing on manganese soils as in 
normal plants. 
The peculiar distribution of the chlorophyll exclusively at the 
lower side of the leaf seems to be characteristic of the family Brome- 
liaceaN so far as we have had opportunity to observe. At any rate 
the chlorophyll is regularly distributed throughout the thickness of 
the leaf or as densely near the upper surface as near the lower sur- 
face in leaves of mango, Croton, Sapium, papaya, Monstera, sisal, 
Sansevieria, oleander, Calophyllum, Eucalyptus, Chrysophyllum, 
Agave americana, canna, Peireskia, banana, prickly pear, CordyUne 
termhialis, and vanilla. In none of these plants, except a few in 
the early stages of growth of the leaves, is there any pronounced de- 
velopment of red coloring matter, which might serve to protect the 
chlorophyll, nor m any of the plants mentioned is the chlorophyll 
restricted to the lower surface of the leaf. It would seem from the 
observations which we have made that the pineapple and closely 
related species of the same family are particularly sensitive plants in 
this respect. The unusually rapid destruction of the chlorophyll 
bodies and the yellowing of the leaves of pineapples, as compared 
with other cultivated plants on manganese soils, also favors this view. 
OXALATE OF LI3IE. 
Chemical analyses Ojl various parts of the pineapple plant show 
that there is a much larger quantity of lime in plants growing on 
manganese soils than in those on normal soils. This finding is partly 
explained and further confirmed by the fact that when examined 
under the microscope all parts of such plants are found to contain 
enormously large numbers of the needlelike crystals of oxalate of 
lime. These crystals are especially numerous in the fruits, but are 
also relatively much more numerous in the leaves of pineapples 
turned yellow from the effects of manganese than in leaves of the 
normal green plants. 
OTHER VISIBLE EFFECTS OF MANGANESE. 
However the effect of manganese on pineapples and other plants 
may be explained, it seems not to be entirely due to the increased 
amount of manganese absorbed by pineapples on highly manganifer- 
ous soils, for the amount of increase of manganese in the ash is not 
sufficiently large to permit such a view to be held. A thorough 
search was made for the possible visible appearance of manganese in 
plants other than pineapples. Minute concretions of manganese were 
found on the ducts and sieve tubes in the roots of mango and straw- 
berry. These concretions were readily dissolved by hydrochloric 
[Bull. 28] 
