The professor would ask you to look at his lectures and satisfy yourself that they contained no single idea that had originated with himself.  “How,” he would ask, “could these valuable lectures have been produced, had I been deprived of the power to avail myself of the facts collected by the working-men, and the principles deduced from them by the thinkers of the world?  I have no leisure to collect facts or analyze them.  For many years past, these lectures have yielded me a large income, and so will they continue to do, provided I be allowed to do in future as in time past I have done, appropriate to my own use all the new facts and new ideas I meet with, crediting their authors or not as I find it best to suit my purpose.  Abandon your idea, my dear sir; it cannot be carried out.  The men who work, and the men who think, must content themselves with fame, and be thankful if the men who write books and deliver lectures do not appropriate to themselves the entire credit of the facts they use, and the ideas they borrow.”

The teacher of natural science would say:  “My friend, have you reflected on what you are about to do?  Look at our collections, and see how they have been enlarged within the last half century.  Asia and Africa, and the islands of the Southern Ocean, have been traversed by indefatigable men who, at the hazard of life, and often at the cost of fortune, have quadrupled our knowledge of vegetable and animal life.  Such men do not ask for compensation of any kind.  They are willing to work for nothing.  Why, then, not let them?  Look at the vast contributions to geological knowledge that have been made throughout the Union by men who were content with a bare support, and glad to have the results of their labors published, as they have been, at the public cost.  Such men ask no copyright.  When they publish, it is almost always at a loss.  Wilson lived and died poor.  So did Audubon, to whose labors we are indebted for so much ornithological knowledge.  Morton expended a large sum in the preparation and publication of his work on crania.  Agassiz did the same with his great work on fishes.  Cuvier had nothing but fame to bequeath to his family.  Lamarck’s great work on the invertebratae sold so slowly that very many years elapsed before the edition was exhausted; but he would have found his reward had he lived to see his ideas appropriated without acknowledgment, and reclothed by the author of ‘Vestiges of Creation,’ of which the sale has been so large.  This, my friend, is the use for which such men as Lamarck and Cuvier were intended.  They collect and classify the facts, and we popularize them to our own profit.  Look at my works and see, bulky as they are, how many editions have been printed, and think how profitable they must have been to the publisher and myself.  Look further, and see how numerous are the books to which my labors have indirectly given birth.  See the many school-books in relation to botany and other