* The general question is dealt with by Mr. Herbert Spencer in his “First Principles,” Chap, xiii., from which the description here given is in part reproduced. Google Scholar

* It would bo out of placo, in a work dealing with the individual organism, to follow these consequences to their operation among races of men, or social organisms. It will be enough to instance the small community of Andorra in the Pyrenees, numbering about 8,000 people, who not only refuse to marry outside of their community, but among themselves marry only their equals in rank, and who are described as an “unchanged and unchanging people.” That the Chinese also have approached equilibratnm is seen both in their remarkable facial similarity and in the fixed character of their institutions. Google Scholar

† It is true that Mr. Herbert Spencer says that while mixed breeds are of larger growth, pure breeds are more hardy, but the whole of Mr. Darwin's evidence is strongly opposed to this view, and as Mr. Spencer merely mentions it very incidentally, without in any way insisting upon it, or adducing any evidence, I think that the opposite view may be taken as the established one. Google Scholar

* It is too well known to be more than mentioned that it is only a sudden change at the central end of a nerve that will cause a shock to be delivered along it to the muscle. A powerful continuous current may be sent along the nerve without effect on the muscle. It is only when the current is made or broken that a contraction ensues, and the more sudden the make or break the more vigorous—other things being equal—is the contraction. Google Scholar