1895.J MICROSCOriCAL JOURNAL. 299 



connected with the parent to form a colony. In the plant 

 world a familiar example of a colony is represented by 

 the cactus that the children call ' Old Hen and Chickens.' 



In the higher animals, however, where specialization 

 has been carried to its extreme limit, some myriads of 

 cells forming the body are set apart to produce motion, 

 others digest food, still others think and feel, while com- 

 paratively few, the germ cells are destined for the con- 

 tinuation of the race. In the higher and highest forms 

 especially, all observation goes to show that the life en- 

 ergy, not satisfied with the mere vitalization of matter 

 and a dead level of excellence, is aiming at perpetual as- 

 cent, greater mastery over matter and its physical forces. 

 For the more certain attainment of this end, the produc- 

 tion of offspring is no longer possible for one individ- 

 ual ; two wholly separate individuals must join, each con- 

 tributing its share of the living matter which is to de- 

 velop into a new being. In this way the accumulated 

 acquirements of two are united with the consequent in- 

 crease in the tendencies and impulses for modification, 

 and nearly double the protection for the offspring. Thus 

 in striking contrast with the amoeba, where the single 

 parent gives all of itself to form offspring, and in so do- 

 ing disappears and loses its individuality, the higher 

 forms, while two must unite to form the offspring, the 

 parents remain and retain their individuality and the 

 ability to produce still other offspring. The process by 

 which this is accomplished may be traced step by step 

 with the microscope. A germ cell of the father and one 

 of the mother fuse together, and from this new procrea- 

 tive cell, formed by the fusion of two with all their pos- 

 sibilities combined, the new individual arises. This cer- 

 tain knowledge is the result of the profound investiga- 

 tion of the last few years and shows the literalness of 

 the scriptural statement, 'they shall be one flesh.' 



After this fusion of the father and mother germ cells, 



