except for his own gratification, and is never gratified with indifferent food so long as he can command that which is to his liking. In further speaking of the "exhausted elements" of the soil--those necessary for the food of trees as well as plants, and without which they inevitably perish and disappear--Mr. Emerson says; "This is clearly indicated in what is constantly going on in the forests, particularly the fact which I have already stated, and which is abundantly confirmed by my correspondents, that a forest of one kind is frequently succeeded _by a spontaneous growth of trees of another kind._" In the sense in which he manifestly uses the term "spontaneous" in this connection, his new forest might be accounted for on the theory of "primordial germs," but not on that of "seeds;" for few trees or shrubs in Massachusetts bear winged seeds, or possess any other means of dispersion (the _Acer_ family excepted) than those common to our general forest growths. Spontaneity, in a strictly scientific sense, is not predicable upon the artificial or chance sowing of either acorns, hickory nuts, or the chits to pine cones. A spontaneous growth implies a process which is neither usual nor accidental--a growth without external cause, but from inherent natural tendency--and it is questionable whether there is any such process in nature. It belongs to the same class of idle speculations as "spontaneous generation" in the infusorial world--a subject that will be considered as we advance in this work. Our vegetable physiologists, Mr. Emerson among the number, are simply unfortunate in their use of terms--those expressing even the commonest operations of nature. In their genesis of plants and trees they need to adhere a little more closely to the genesis of induction, and use language in harmony with the phenomenal facts and characteristics which they are called upon to explain. But Mr. Emerson was not alone at fault in this almost universal slip of the scientific pen. He quotes from a letter of Mr. P. Sanderson, of East Whately, Mass., in which the writer says: "There is an instance on my farm of spruce and hackmatack being succeeded by a spontaneous growth of maple wood;" and he adds that "instances are also mentioned by him (Mr. Sanderson) of beech and maple succeeding oaks; oaks following pines, and the reverse; hemlock succeeded by white birch in cold places, and by hard maple in warm ones; beech succeeded by maple, elm, etc; and, in fact, the occurrence was so common that surprise was expressed at the asking of the question."