“In the seventh week bone begins to form in the lower jaw and clavicle. Narrow streaks on each side of the vertebral column show the beginning of the ribs. The heart is perfecting its form, the brain enlarging and the eyes and ears growing more perfect, and the limbs sprouting from the body. The lungs are mere sacs, about one line in length, and the trachea is a delicate thread, but the liver is very large. In the seventh week are formed the renal capsules and kidneys.
“At two months the forearm and hand can be distinguished, but not the arm; the hand is larger than the forearm, but it is not supplied with fingers. The distinction of sex is yet difficult. The eyes are prominent. The nose forms an obtuse eminence. The nostrils are rounded and separated. The mouth is gaping and the epidermis can be distinguished from the true skin. The embryo is from one and a half to two inches long and weighs from three to five drachms, the head forming more than one-third of the whole.
“At the end of three months the eyelids are distinct but shut; the lips are drawn together; the forehead and nose are clearly traceable, and the organs of generation prominent. The heart beats with force, the larger vessels carry red blood; the fingers and toes are well-defined, and muscles begin to be developed.
“At the fourth month the embryo takes the name of fetus. The body is six to eight inches in length and weighs from seven to eight ounces. The skin has a rosy color, and the muscles produce a sensible motion. A fetus born at this time might live several hours.
“At five months the length of the body is from eight to ten inches, and its weight from eight to eleven ounces.
“At six months the length is twelve and a half inches; weight, one pound. The hair appears upon the head, the eyes closed, the eyelids somewhat thicker, and their margins, as well as the eyebrows, are studded with very delicate hairs.
“At seven months, every part has increased in volume and perfection; the bony system is nearly complete; length, twelve to fourteen inches; weight, two and a half to three pounds. If born at this period the fetus is able to breathe, cry and nurse, and may live if properly cared for.
“At eight months, the fetus seems to grow rather in length than in thickness; it is only sixteen to eighteen inches long and yet weighs from four to five pounds. The skin is very red, and covered with down and a considerable quantity of sebaceous matter. The lower jaw, which at first was very short, is now as long as the upper one.
“Finally, at term the fetus is about nineteen to twenty-three inches long, and weighs from six to nine pounds. The red blood circulates in the capillaries, and the skin performs the functions of perspiration; the nails are fully developed.”
There is a superstition that a child born at eight months is not as liable to live as if born at seven months; indeed, many suppose that an eight months’ child never survives. Facts do not prove this idea correct.