Limiting Factors in the History of Science^ 

 as Observed in the History of Embryology 



(Carmalt Lecture at Yale University, 1935) 



Probably the best way to summarise the influences which have 

 operated in the history of embryology is to concentrate attention on 

 what may be called, borrowing a phrase from general physiology, 

 the "limiting factors" of advance. We may thus regard the progress 

 of knowledge about generation as governed by a reaction-chain, one 

 link of which may at any given time be slower tlian all the others, 

 and hence may set the speed for the whole. 



Relation of investigators to their environment 



Limiting 

 factors 



Co-operation of investigators 



Technique 



Practical 



Theoretical < 



Terminological 



Conceptual 



Psychological 



Constructive 

 Destructive 



Balance between Speculation, Observation, and Experiment 



Scientists and their Environment. 



Of these limiting factors the first which may be mentioned is the 

 relation of investigators to their environment. The Carlylean tendency 

 to regard the history of science as a succession of inexplicable geniuses 

 arbitrarily bestowing knowledge upon mankind has now been generally 

 given up as quite mythological. A scientific worker is necessarily the 

 child of his time and the inheritor of the thought of many generations. 

 But the study of his environment and its conditioning power may be 

 carried on from more than one point of view. 



A sharp distinction is made by the culture-historians, between 

 the mental atmosphere of the Renaissance, the Baroque, the Rococo, 



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