The kangaroo and oppossum are provided with a pouch attached to the abdomen, which receives the young born at an early stage of development. They remain in contact with the mammæ, from which they obtain their nourishment, until their growth is sufficiently completed to maintain an independent existence. This is called marsupial generation. The variety of reproduction which is most interesting, is that of the human species, and is called viviparous generation. It includes the functions of copulation, fecundation, gestation, parturition, and lactation.
For the full and perfect development of mankind, both mental and physical chastity is necessary. The health demands abstinence from unlawful intercourse. Therefore children should not be allowed to read impure works of fiction, which tend to inflame the mind and excite the passions. Only in total abstinence from illicit pleasures is there moral safety and health, while integrity, peace, and happiness, are the conscious rewards of virtue. Impurity travels downward with intemperance, obscenity, and corrupting diseases, to degradation and death. A dissolute, licentious, free-and-easy life is filled with the dregs of human suffering, iniquity, and despair. The penalties which follow a violation of the law of chastity are found to be severe and swiftly retributive.
The union of the sexes in holy matrimony is a law of nature finding sanction in both morals and legislation. Even some of the lower animals unite in this union for life, and instinctively observe the law of conjugal fidelity with a consistency which might put to blush other animals more highly endowed. It is important to discuss this subject and understand our social evils, as well as the unnatural desires of the sexes, which must be controlled or they lead to ruin. Sexual propensities are possessed by all, and they must be held in abeyance, until they are exercised for legitimate purposes. Hence parents ought to understand the value of mental and physical labor to elevate and strengthen the intellectual and moral faculties of their children, to develop the muscular system and direct the energies of the blood into healthful channels. Vigorous employment of mind and body engrosses the vital energies and diverts them from undue excitement of the sexual desires.
Sexual generation by pairing individuals is the most economical mode of propagating the species. The lower orders of animals possess wonderful multiplicative powers and their faculty for reproduction is offset by various destructive forces. The increased ability for self-maintenance implies diminished reproductive energy; hence the necessity for greater economy and safety in rearing the young. As certain larvæ and insects increase, the birds which feed upon them become more numerous. When this means of support becomes inadequate, these same birds diminish in number in proportion to the scarcity of their food. Many have remarked that very prolific seasons are followed by unusual mortality, just as periods of uncommon prosperity precede those of severe disaster.