Martin, who regards the phenomenon as normal, points out that when nausea and vomiting are absent or suddenly cease there is often reason to suspect something wrong, especially the death of the embryo. He also remarks that women who suffer from large varicose veins are seldom troubled by the nausea of pregnancy. (J.M.H. Martin, "The Vomiting of Pregnancy," _British Medical Journal_, December 10, 1904.) These observations may be connected with those of Evans (_American Gynæcological and Obstetrical Journal_, January, 1900), who attributes primary importance to the undoubtedly active factor of the irritation set up by the uterus, more especially the rhythmic uterine contractions; stimulation of the breasts produces active uterine contractions, and Evans found that examination of the breasts sufficed to bring on a severe attack of vomiting, while on another occasion this was produced by a vaginal examination. Evans believes that the purpose of these contractions is to facilitate the circulation of the blood through the large venous sinuses, the surcharging of the relatively stagnant pools with effete blood producing the irritation which leads to rhythmic contractions. It is on the basis of the increased vascular and glandular activity and the heightened nervous tension that the special psychic phenomena of pregnancy develop. The best known, and perhaps the most characteristic of these manifestations, is that known as "longings." By this term is meant more or less irresistible desires for some special food or drink, which may be digestible or indigestible, sometimes a substance which the woman ordinarily likes, such as fruit, and occasionally one which, under ordinary circumstances, she dislikes, as in one case known to me of a young country woman who, when bearing her child, was always longing for tobacco and never happy except when she could get a pipe to smoke, although under ordinary circumstances, like other young women of her class, she was without any desire to smoke. Occasionally the longings lead to actions which are more unscrupulous than is common in the case of the same person at other times; thus in one case known to me a young woman, pregnant with her first child, insisted to her sister's horror on entering a strawberry field and eating a quantity of fruit. These "longings" in their extreme form may properly be considered as neurasthenic obsessions, but in their simple and less pronounced forms they may well be normal and healthy.