by their dreadful spines, an insuperable obstacle to the intruder. Lastly, the medicine-chest does not go away empty, for the physicians of America make abundant use of the acid juice for fomentations in inflammations, not to mention some other prescriptions. In the same way that grass and clover are not immediately valuable to man, but serve as food for useful animals, so it is with a number of cacti, which support an insect of extraordinary importance. This is the cochineal insect (Coccus Cacti), a little, very insignificant creature, externally just like the little, white, cottony parasite, which is so often found upon the plants in our hothouses, and yet, through the invaluable coloring matter it contains, so infinitely different from it. While the ugly form, the splendor of the blossom, and the manifold uses of the cactus plants attract general interest in a high degree, they are not less interesting, in a narrower sphere, to the botanist. Zoologists have at all times found in the examination of monstrosities and aberrant forms rich material toward the clearing and expanding of their knowledge of the regularly developing organism. It is to be expected, therefore, that similar conditions will have similar value in the vegetable world; and what family could be better selected for this purpose than the Cactaceæ, which seems to be but a natural museum of monstrosities, where the forms are, in some cases, so abnormal that no other name could be thought of for one species but that of the deformed cactus (Cereus monstrosus)?