AS GENETICS COMES OF AGE 



E. M. East 

 Bnssey Instiintion, Harvard University, Forest Hills, Mass. 



GENETICS was born twenty-one 

 years ago when there came the 

 first real appreciation of the 

 studies on heredity made in the httle 

 garden at Briinn. Now that it has 

 reached full manhood and is ready to 

 assume the toga virilis, the time seems 

 fitting to call back the yesterdays, to 

 cast up accounts, and to judge whether 

 the performance of maturity promises 

 to repay the cost of infancy and child- 

 hood. 



Perhaps it will serve our purpose to 

 contrast the status of affairs toward 

 the close of the long prenatal period 

 previous to the twentieth century, 

 with that of today. When one does 

 this, he is convinced that our chance 

 metaphor is really rather apt. When 

 the chick breaks through the egg, when 

 the butterfly bursts the chrysalis, when 

 the rose bud opens, the change is super- 

 ficially so revolutionary that one is 

 likely to forget the intensive energy ex- 

 pended in preparation for the natal day. 

 So also with the study of heredity. 

 Genetics was born and christened be- 

 cause of Gregor Mendel. Not because 

 he diligently gathered facts regarding 

 the heredity of the garden pea; rather 

 because he was able to analyze and 

 correlate these facts. Others had 

 gathered facts galore. Indeed the 

 growth-curve of knowledge had been 

 rising steadily for many years. Yet 

 metamorphosis came only when mathe- 

 matics began to be applied effectively 

 to the efforts of physiologist and mor- 

 phologist. Change in method rather 

 than a single great discovery gave the 

 first real insight into the master riddle 

 of the ages. 



EARLY STUDIES OF HEREDITY 



PreA'ious to the beginning of the 

 twentieth century, isolated observa- 

 tions on heredity had been made by 

 many types of workers. It was only 

 natural that this should be the case. 



Such a seemingly mysterious force 

 could hardly have failed to fascinate 

 mankind from the very beginning of 

 his speculative history. But isolated 

 observations on subjects wherein are 

 numerous complex variables, usually 

 wait long for the keystone with which 

 the generalizing mind can support an 

 edifice of useful theory. And in this 

 particular instance the time was un- 

 doubtedly extended by a striking 

 aloofness and lack of a spirit of co- 

 operation among the laborers in the 

 various guilds. 



The first tier of foundation stones 

 was laid by the breeder. As was to 

 have been expected, the empiricism of 

 a practical art led the judicial classifi- 

 cation and the inductive reasoning of 

 science. One has only to study the 

 wonderful domestic animals in the 

 paintings and reliefs of Babylonia, 

 of Assyria, of Egypt, to realize that 

 knowledge of the effects of selection 

 has been extant for at least six 

 thousand years, perhaps for ten or 

 twenty thousand years. And Jacob's 

 little scheme to mulct his father-in-law 

 of the ring-straked and spotted cattle 

 shows us somewhat of the older 

 theoretical beliefs. Jacob, in fact, 

 seems to have been as advanced a 

 geneticist as many of the animal 

 breeders of the nineteenth century; 

 since the textbooks of this period 

 express a similar belief in maternal 

 impressions and other fables, and con- 

 tain not a single conclusion that one 

 can now point out as having a per- 

 manent value. 



Generally speaking, the history of 

 plant breeding gives a little more cause 

 for pride. True, the early Semitic 

 knowledge of plant sexuality was 

 actually lost until the latter part of 

 the seventeenth century; but having 

 rediscovered this fundamental truth 

 through the work of Camerarius, 

 the eighteenth and nineteenth century 



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