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.
VI
HUMAN TERATA AND THE SACRAMENTS
Teratology (
, 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.
Mammalian ova, owing to an almost complete lack of yolk, are all small. The egg of a whale is about the size of a fern-seed, but the yolked eggs of birds are large—that of the great auk was 7.5 inches long. In man the ovum is from 0.18 to 0.2 mm. in diameter, scarcely visible to the [{70}] naked eye, and the spermatozoon is extremely minute. The human spermatozoon is only fifty-four thousandths of a millimetre in length, and from forty-one to fifty-three thousandths of a millimetre are taken up by its flagellum. The essential part is from four to six thousandths of a millimetre in length (Dr. L. N. Boston, Journ, of Applied Microscopy, vol. iv. p. 1360). A line of 18 human spermatozoa would reach only across the head of an ordinary pin. These spermatozoa have the power of locomotion in alkaline fluid. Henle found they can travel one centimetre in three minutes.