It is hoped that the account given, in the following pages, of the lives of five great naturalists may not be found devoid of interest. The work of each one of them marked a definite advance in the science of Biology. There is often among students of anatomy and physiology a tendency to imagine that the facts with which they are now being made familiar have all been established by recent observation and experiment. But even the slight knowledge of the history of Biology, which may be obtained from a perusal of this little book, will show that, so far from such being the case,.
