"It may be of interest to your readers to know that two guinea-pigs were born at Oxford a day or two before the death Dr. Romanes, both of which exhibited a well-marked droop of the left upper eyelid. These guinea-pigs were the offspring of a male and a female guinea-pig in both of which I had produced for Dr. Romanes, some months earlier, a droop of the left upper eyelid by division of the left cervical sympathetic nerve. This result is a corroboration of the series of Brown-Séquard's experiments on the inheritance of acquired characteristics. A very large series of such experiments are of course needed to eliminate all sources of error, but this I unfortunately cannot carry out at present, owing to the need of a special farm in the country, for the proper care and breeding of the animals.--LEONARD HILL. "Physiological Laboratory, Univ. Coll. London, Oct. 18, 1894."] CHAPTER V. CHARACTERS AS HEREDITARY AND ACQUIRED (_continued_). (A. and B.) _Direct and Indirect Evidence in favour of the Non-inheritance of Acquired Characters_[81]. [81] [_See_ note appended to Preface. C. LI. M.] The strongest argument in favour of "continuity" is that based upon the immense difference between congenital and acquired characters in respect of heritability. For that there is a great difference in this respect is a matter of undeniable fact. And it is obvious that this difference, the importance of which must be allowed its full weight, is just what we should expect on the theory of the continuity of the germ-plasm, as opposed to that of pangenesis. Indeed it may be said that the difference in question, while it constitutes important _evidence_ in favour of the former theory, is a _difficulty_ in the way of the latter. But here two or three considerations must be borne in mind. In the first place, this fact has long been one which has met with wide recognition and now constitutes the main ground on which the theory of continuity stands. That is to say, it was the previous knowledge of this contrast between congenital and acquired characters which led to the formulation of a theory of continuity by Mr. Galton, and to its subsequent development by Prof Weismann.