IN a note contributed to the Bulletin of Hygiene for February, Lettin M. Crump discusses the intro duction of pre-marital health certificates from the point of view of eugenics. In Mexico, impediments to marriage include insanity, and similar restrictions extending to imbecility or feeblemindedness are found in certain of the United States. The growing practice of requiring a certificate from a qualified medical practitioner for insurance purposes, as well as from candidates for public appointments, seems likely to undermine opposition on this score, and with a more enlightened public opinion the need for compulsion would be greatly lessened. In some countries, notably Austria, Germany and some of the United States, the establishment of centres for giving advice on all matters concerning marriage has found favour. Useful advice can only be given when the investigator has a knowledge of the applicant's physical and mental condition as well as of his hereditary background and that of his proposed partner, the type of inheritance of any heritable disease or defect which may be present in the pedigree and of the effect which other causes may have upon the appearance of such heritable conditions. Mendelism provides us with a growing body of available information concerning inheritance in man, and evidence collected in the working of marriage advice bureaux leads to the conclusion that feeble mindedness is in many cases inherited and usually behaves as a recessive; the mating of possible heterozygotes is undoubtedly to be discouraged. Although evidence collected from pedigrees is fre quently both vague and faulty, justice demands that every available means of making public such information as exists should be fully used so as to enable the conscientious citizen to avoid handing on defects from generation to generation.