396 



The Journal of Heredity 



It seems to be a universal habit to 

 ascribe a cause to every effect and 

 one's peace of mind is satisfied in this 

 way, whether there is any real proof of 

 the connection between the two or not. 



This collection of photographs of 

 some of the more interesting of the 

 150 photographs of twins is pub- 

 lished with the object of bringing to 

 the attention of the readers of The 

 Journal of Heredity the existence of 

 thousands of hurfian beings who have 

 gone through changes of environment 

 which we have been in the habit of con- 

 sidering sufficient to acount for all sorts 

 of effects without varying enough . in 

 their likenesses to each other to make 

 them easily distinguishable. 



These photographs are published for 

 the purpose of putting into the minds of 

 as many people as possible this illustra- 

 tion of the force of heredity, so that 

 they will appreciate the importance of 

 the work of those men who are pushing 

 into the field of its study. The field is 

 worthy of the attention of the most 

 brilliant minds of this age, and those 

 who are successful in increasing the 

 sum of our knowledge of it will most 

 certainly be benefactors of the human 

 race. 



Should we not always remember that 

 the sum total of our knowledge as com- 

 pared to the future acquisitions of the 

 human mind is as nothing; that we 

 stand looking out on the world 

 with the same blindness of vision 

 that the mariners had when they 

 saw every day the masts of the ap- 

 proaching vessels before the hulls ap- 

 peared and failed to interpret the fact 



to mean that they were sailing round a 

 gigantic globe? 



I have some such impression when I 

 look at this collection of the photo- 

 graphs of identical twins — identical 

 from their babyhood through to old 

 age. A study of them cannot be a 

 trivial thing, and somewhere there 

 must be a mind which will assemble 

 the facts about them and bring these 

 to bear on the greatest problem of the 

 world, which is the understanding of 

 what constitutes human progress. 



■ . GOOPERATION FROM THE TWINS 



To those who have so generously 

 volunteered themselves — and there 

 were over 600 of them — as subjects for 

 the study of the specialists of the Amer- 

 ican Genetic Association, I wish to ex- 

 press the deepest gratitude. Nothing 

 has occurred since the establishment of 

 the association which has so encour- 

 aged its officers as this response from 

 the Twins of the World. It has given 

 them a feeling of confidence that there 

 is deep in the consciousness of every- 

 one a keen interest as to what character 

 of human race is to inhabit the globe 

 after we are gone. That this interest 

 will grow until it occupies the high- 

 est and most important place in human 

 consciousness is the conviction of 

 students of the new science of genetics. 



The special studies made from the 

 data supplied by the Cooperating Twins 

 will be published from time to time in 

 The Journal of Heredity, and such 

 of the photographs as have been given 

 to the association will be kept for ref- 

 erence purposes. 



