of evolution. For years he blocked the progress along all lines but his own restricted field of anatomy, and waged bitter warfare on anyone who dared to oppose him. And so the blind Lamarck lived in poverty and obscurity, neglected by both scientists and those who knew nothing of zoology. And through this he stood faithfully by the ideas which he believed but was too poor and unknown to defend.
Lamarck first held to the old teaching that species were fixed, and could neither change nor be changed. But as he learned more his views changed, and in 1809 he published a book stating his interpretation of evolution. One of his principal ideas was that the effects of the use or disuse of any part of the body may be passed on from parent to children until they finally become parts of the animal's make-up. It is well known that an arm that is never used becomes weak; that a muscle which is constantly at work becomes strong and large. Lamarck supposed that this increase or decrease in size could be inherited, and thus races with short, thin arms, or heavy powerful muscles could be developed. This is the "theory of inheritance of acquired characteristics" again, first formulated by Erasmus Darwin. Just how much there is to this theory no one has been able to say; some believe it to be worthless while others, particularly those who study fossil animals, think that it possesses a certain amount of truth.
Lamarck was, as we have said, a conscientious scientist, and made use of his own accurate
