BULLETIN OF THE BUSSEY INSTITUTION. 185 
matter, found that the organic matter was of the same composition as 
cellulose, and that it contained no nitrogen whatsoever. 
The agricultural value of the nitrogen in the shells is unknown. It 
is probably not very great, as compared with the value of the nitrogen 
in guano, nitrates, and ammonium salts. Whatever the value may be, 
it can only be determined by experiments which shall test directly the 
influence of this form of nitrogenous matter upon the growth of vegeta- 
tion. It is to be remembered, in this connection, that, practically, the 
crabs or horseshoes, and in many cases the shell-fish also,* which the 
farmer brings to his land, usually contain more or less flesh adhering 
to them, sometimes in the fresh condition, and sometimes dry ; and 
that this flesh might in some cases supply to the land a considerable 
amount of nitrogen of approved quality. Nevertheless, it is plain 
that, as the general rule, sea-shells must be regarded simply as a cal- 
careous manure, that may be used with advantage in certain localities 
instead of lime or marl. The other fertilizing matters, beside carbon- 
ate of lime, which are contained in the shells have undoubtedly a cer- 
tain small value of their own which tends to enhance the worth of the 
shells somewhat; but the amounts of these supplementary matters are 
so small that very little importance can be attached to them. In case, 
indeed, a farmer had to choose between lime from sea-shells, and that 
from a lime-stone proper, the known presence of the small quantities of 
phosphoric acid, &c., in the shells would naturally lead him — other 
things being equal — to prefer the shell-lime, unless he had some evi- 
dence that the other form of lime accessible to him contained as 
* This remark applies with especial force to the so-called mussel-bed, which 
is often used as a fertilizer, with great advantage, upon the New England coast, 
as may be seen in several of the Reports of the State Boards of Agriculture of 
Maine and Connecticut. The ‘ mussel-bed” consists of impacted masses of 
living mussels dug at low-water from the large beds in which this kind of shell- 
fish habitually congregates. Its efficacy as a manure may manifestly depend 
upon either one or both of two causes. The flesh of the mussel is a nitro- 
genous manure, of quick action; and to it is to be attributed the rapid and ener- 
getic effects which have often been noticed when land has been dressed with 
this fertilizer. On the other hand, the delicate, friable shells of the mussel un- 
doubtedly often play the part of a calcareous manure, such as mar! or leached 
ashes ; and to this cause the well-known lasting or durable effect of the ‘“mussel- 
bed” must be referred. The fact that mussel-bed has sometimes been found 
specially useful upon clayey soils may be due in part to an improvement in the 
texture of the clay, brought about by the mere loosening or mechanical action 
of the broken shells. Compare Wilda’s “ Landwirthschaftliches Centrallblatt,” 
1858, 6. (ii.) 32. 
