There is no doubt, however, that the mother's environment during pregnancy is in general very important for the perfect development of the intrauterine child. Many more deformed births are reported after times of stress and trial, as, for example, after the sieges of great cities, notably the siege of Paris in 1871, and such scenes of desolation as occurred during the thirty years' war in Germany. These are, however, not direct, but indirect effects of maternal impressions. The development of the human being _in utero_ is an extremely complicated process. Any disturbance of it, however slight, is sure to be followed by serious consequences. Disturbances of nutrition, such as are consequent upon the deprivation that has to be endured in times of war or during sieges, is of itself sufficient seriously to disturb even the uterine life of the child. In these cases, however, there will be no traceable connection between the form of the maternal impression and the type of deformity that occurs. This is, however, the essence of the old theory of the direct effect of maternal impressions, and consequently that theory must fall to the ground. From all that has been said, however, it becomes very clear that as far as possible women should be shielded from the effect of various nervous shocks during their pregnancy, and that they owe it to themselves and their offspring to be careful with regard to any morbid manifestations of feeling that they may detect in themselves. JAMES J. WALSH. {69} VI HUMAN TERATA AND THE SACRAMENTS Teratology ([Greek text], a monster) is a part of biology that treats of deviation from a normal development in man and the lower animals. The name was adopted in 1822 by the elder Saint-Hilaire, who then attempted to separate the results of modern exact methods of research from the myths and loose descriptions of monsters found in the writings of old authors. Cicero (_De Divinatione_) derives the term monster from the proper preternatural signification looked for in the occurrence of these abnormal beings: "Monstra, ostenta, portenta, prodigia appellantur, quoniam monstrant, ostendunt, portendunt et predicunt." At the end of the seventeenth century Malpighi and Grew discovered that plant tissue is entirely made up of microscopic spaces enclosing fluid; they called these spaces _cells_. Different investigators found that animal tissue is also composed of cells; and between 1835 and 1839 Schwann and Schleiden formulated the law that every metazoic organism is made of cells, and starts from a cell. In 1672 de Graaf discovered the mammalian ovum, in 1675 Ludwig Ham found spermatozoa, in 1827 von Baer recognised the human ovum, but not until 1875 was the important fact established that fertilisation is effected by the fusion of the male and female pronuclei. This was demonstrated by Oscar Hertwig from observation of the ova of starfishes.