useful insects.  That is, the limited partnership of Oxygen, Hydrogen, & Co., under which they agreed to carry on the operations of sheep, fox, or fish, having terminated by the death of the animal, the partners make immediate use of their liberty and go off in inorganic form in search of new engagements, leaving sulphur, phosphorus, and the other subordinate elements of the animal, to shift for themselves.  They were in the employ of a sheep; they will now carry on a man or an oak-tree, a colony of insects, or something else.  Under the form of carbonate of ammonia, the four elements diffuse themselves through the air, or are absorbed by the earth, and offer themselves at once to the roots and leaves of the trees, as ready to go on with their vivifying operations as they were in behalf of the animals.  There are some plants which seem not to be left to the chances of securing their nourishment from the carbonate of ammonia that the air and the soil contain, but are contrived so as to entrap living animals and hold them fast while they undergo decomposition, so that all their gases may be absorbed by them alone.  Thus, “the little Sundew exudes a gluey secretion from the surface of its leaves, which serves to attract and retain insects, the decay of whose bodies seems to contribute to its existence.”  And the Dionaea, or Venus’s Fly-trap of the Southern States, has some leaves which fold together upon any insect that alights upon their upper surface; and by means of a row of long spines that fringes the leaves, they prevent his escape.  The more active the struggles of the captive, the closer grows the hold of the leaf, and speedily destroys him.  The plant appears to derive nutriment from the decomposition of its victims.  “Plants of this kind, which have been kept in hot-houses in England, from which insects were carefully excluded, have been observed to languish, but were restored by placing little bits of meat upon their traps,—­the decay of these seeming to answer the same purpose.”

The four elements already referred to are by no means all the material ingredients of animal bodies.  There are, also, phosphorus, lime, magnesia, soda, sulphur, chlorine, and iron; and if you believe some chemists, there is hardly a mineral in common use that may not be found in the human body.  We doubt, however, whether lead, arsenic, and silver are there, without the intervention of the doctor.

What becomes of the phosphorus and the rest, when an animal dies?  Oh, they take up new business, too.  They are as indispensable to the animal frame as the four most prominent ingredients.  We eat a great deal of bread and meat, and a little salt,—­but the little salt is as important to continued life as the large bread.  There is hardly a tissue in the body from which phosphorus, in combination with lime, is absent; so that the composition of lucifer-matches is by no means the most important use of this element.  The luminous appearance which some putrefying substances, particularly fish, present at night, is due to the slow combustion of phosphorus which takes place as this element escapes into the air from the decomposing tissues.