JUGGLING WITH LIFE 



apple blossoms, we may rest assured that provision 

 is being made for a good crop of fruit the coming 

 fall. And everyone who has lived in the country 

 must have observed that protracted rain storms just 

 at the time when the apple trees are in bloom may 

 keep the insects from performing their unconscious 

 service, and thus may prevent the possibility of a 

 good apple crop that year. 



These familiar illustrations from the vegetable 

 world suggest what indeed is matter of common 

 knowledge the almost universally prevailing plan 

 of Nature according to which the union of two di- 

 verse types of elements is essential to the production 

 of offspring. Every-day phraseology speaks of these 

 as male and female elements. The biologist, using 

 the same terminology for animals and plants, calls 

 the female element an ovum or germ cell and the 

 male element a spermatozoon or sperm cell. 



Biologists and laymen have been at one in suppos- 

 ing the union of the two elements to be absolutely 

 essential to the development of offspring in the case 

 of higher organisms, with the exception of certain 

 insects about which we shall have more to say in a 

 moment. 



CAUSING UNFERTILIZED EGGS TO DEVELOP 



Hence the astonishment with which scientific and 

 unscientific readers alike received the intelligence, in 

 1899 and 1900, that one of the most painstaking in- 

 vestigators among contemporary biologists, Profes- 

 sor Jacques Loeb, then of the University of Chicago, 

 later of the Rockefeller Institute, New York, had 



