The law of human increase, or population based on physiology and psychology / by Nathan Allen.

  • Allen, Nathan, 1813-1889.
Date:
1868
Catalogue details

Licence: Public Domain Mark

Credit: The law of human increase, or population based on physiology and psychology / by Nathan Allen. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    48/62 (page 44)
    any evidence can he adduced to show that it violates a single principle in physiology. If, then, such an organism constitutes the stand- ard for healthy for longevity, for strength, and for beauty, and is also in harmony with all the known laws of physiology, may it not constitute the only true and natural basis of Imman increase ? This theory of population is confirmed bylaws drawn from both tlie vegetable and animal creation. The New York Post, of October 18th, 1867, in commenting upon the j)aper already referred to, presented at the Social Science meetino-in Boston, sugjsrested that there might be other causes than what were enumerated to account for the change in population, and presented the following summary of facts from Mr. Doubleday’s work. Says Mr. D., “ it is a fact admitted by all gar- deners as well as botanists, that if a ti’ee, plant, or flower, be placed in a mould, either naturally or arti- ficially made too rich for it, a plethoric state is pro- duced, and fruitfulness ceases. In trees, the effect of strong manures, and over rich soils, is, that they run to superfluous wood, blossom irregularly, and almost or entirely cease to bear fruit. In flowering shrubs and flowers, the first effect is, that the flower becomes double, and loses its jiower of producing seed; next it ceases almost even to flower. On the other hand, when a gardener wishes to save seed, he does not give the plant an extra dose of manure, but he subjects it to some hardshij), and selects the fruit that is least fine looking, knowing that it will be filled with seed, while the finest fruit will be nearly destitute.”