106 HALF HOURS WITH INSECTS. [Packard. 



Regarding this estimate of what one Aphis can do to pop- 

 ulate the world, Prof. Huxley makes the following state- 

 ment : "I will assume that an Aphis weighs one-thousandth 

 of a grain, which is under the mark ; a quintillion will on 

 this estimate weigh a quadrillion of grains. He is a very 

 stout man who weighs two million grains ; consequently the 

 tenth brood alone, if all its members survive the perils to 

 which they are exposed, contains more substance than five 

 hundred million stout men, to say the least more than the 

 whole population of China." That the individual with the 

 potential ability to produce such A mass of young only suc- 

 ceeds in leaving perhaps two eggs to represent its species at 

 the beginning of winter, all its offspring dying off, is a sig- 

 nificant fact, illustrating forcibl}^ the tei-rible struggle for ex- 

 istence going on in the animal world. 



I scarcely know how to present in a popular way the mode 

 of growth of the embryo Aphis. It has been Avell described 

 by Huxley, and in a more exhaustive manner by the Russian 

 naturalist Metznikoff. This study of the earliest phases in 

 the life of an insect, or in fact any animal, leads us up to 

 the very threshold of the m3-sterious portals of life. The 

 problem given is, a sac full of protoplasm, a drop of jelly 

 like the jelly in the cell of a plant, to our eyes the same, so 

 far as our finite analysis at present extends, and 3'et poten- 

 tially an animal, even representing the initial point of man 

 himself. How is this result attained? This drop of oily 

 jelly contains another sac filled with albumen, called the 

 nucleus. Now when that mysterious act, the mingling of 

 the contents of a sperm cell with the ovarian cell, or as in 

 the virgin Aphis, the act of budding — the simplest genera- 

 tive process known — has occurred, let us with the practised 

 eve of our Russian guide watch the behavior of the two ele- 

 ments, the general oily contents of the cgg^ or yolk, and the 

 albuminous nucleus. The original protoplasmic mass has, 

 prior to the union with a sperm cell, increased in size and 



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