280 THE AMERICAN MONTHLY [Sept. 



two. The original amoeba is no more ; in its place there 

 are two. Thus nearly at the bottom of the scale of life 

 are manifested all the fundamental features, the living 

 substance moves itself, takes nourishment, digests it and 

 changes non-living into living substance and increases 

 in size ; it seems to feel and avoid the disagreeable and 

 choose the agreeable and finally it performs the miracle 

 of reproducing its kind, of giving out its life and sub- 

 stance to form other beings, its offspring 



"The processes and phenomena by which a new indi- 

 vidual is produced are included under the comprehensive 

 term, Embryology. 



"All organisms, great or small, are but developments 

 of minute germs budded off by the parent or parents, 

 and the way in which these minute beginnings develop 

 into perfect forms like their parents can only be followed 

 by the aid of a microscope. Indeed, in no field of bio- 

 logy has the microscope done such signal service in re- 

 vealing the processes of life 



"Fortunately for the histologist the incessant experi- 

 mentation of the last twenty-five years has brought to 

 knowledge chemical substances which do for the tissues 

 the wonder that was ascribed to the mythical Gorgon's 

 head — to kill instantly and to harden into changeless 

 permanence all that gazed upon it. So the tissues may 

 be fixed at any phase, and then studied at length. If 

 then the investigator observes and keeps record of every 

 point that may have an influence on the structural ap- 

 pearances, whether shown by experience or suggested by 

 insight, and this record always accompanies the speci- 

 men, thus and thus only, it seems to me, can he feel con- 

 fident that he is liable to gain real knowledge from the 

 study, knowledge that represents actuality and which 

 will serve as a basis for a newer and more complete un- 

 raveling of the intricacies of structure, an approximate 



