ZOOLOGY 381 



pregnation does it become in any case a true developing egg; and it would 

 see in that, in a few cases at least, it may develop either gemmatively, or in 

 true egg style, that is, it may continue a germ-bud, or become an egg, ac- 

 cording as it is or is not impregnated. 



But, while this extension of the budding method of propagation subserves 

 an end of vast importance among the inferior animals and in the plant king- 

 dom, it cannot be properly an equivalent to the normal sexual process. 

 There is some great difference between what the female can bud out of her- 

 self, and what the sexes combined produce. It is probable, from facts which 

 have been observed, both in plants and animals though not yet demon- 

 strated that bud propagation will in all cases, if followed exclusively, end 

 in th'e decline of the race, and its ultimate extinction ; and that the sexes 

 are required to keep up the sexual system and thus to sustain the type at its 

 normal level, and secure its perpetuity. This, if established as a real effect, 

 is yet but a partial, or inadequate expression of the difference between the 

 two results. The subject opens a wide field for exploration. Silliman's 

 Journal (abridged), Nov., 1857. 



SILK CULTURE IN INDIA. 



Mr. F. Bashford, who has been engaged in the silk culture in India for 

 many years, states, in a paper recently presented to the London Society of 

 Arts, that it requires in Bengal 10,000 of the best cocoons to produce one 

 pound of good silk; in France 2,500 cocoons produce the same quantity. 

 With a view to improve this produce, Mr. Bashford imported a large quan- 

 tity of the best French, Italian, and China eggs, to engraft upon the different 

 species of the Bengal race. Various details of the experiments were then 

 given; but Mr. Bashford sums up by saying that, as he had spent three 

 years in trying ineffectually to engraft a superior nature, and invigorate the 

 common stock, he felt discouraged, and would gladly have the opinion of 

 naturalists as to the probability of his object ever being attainable, and the 

 proper" steps to be taken for realizing it. 



BUTTERFLY VIVARIUM. 



The success of vivaria for fish and Crustacea, has suggested to Mr. Noel 

 Humphreys, of England, the idea of a vivarium for insects ; and for the con- 

 struction of this he has recently published directions in a work entitled the 

 "Butterfly Vivarium," or "Insect Home." Entomologists have at all times 

 found it necessary to make use of some kind of vivarium, for the purpose of 

 observing the changes which insects undergo before arriving at their perfect 

 state. The tin box, with a perforated lid for ventilation, the card-board 

 trays for silkwoi-ms, or the wooden box sunk in the ground, with a wire 

 lid, and filled with the various kinds of caterpillars, are, in fact, all vivaria. 

 But the speciality of Mr. Humphreys' plan is to make the vivarium an orna- 

 mental object for a drawing-room. "With this view, he proposes that it shall 

 consist of a glass case, with proper ventilation at the top; that part of the 

 bottom shall be filled with earth, in which plants, such as are fed upon by 

 insects, shall be planted; that another part shall be devoted to a tank, for 

 the benefit of such as delight in water; and that in the earth shall be in- 

 serted bottles for holding sprigs of such plants as ai*e too large to grow in the 

 vivarium. We cannot gather from the directions whether or not Mr. Hum- 



