The Psychological Consequences of Heredity. 321 



Dr. Broca compared together one hundred and twenty-five 

 skulls from the crypt of the old church of Saint-Barthe'lemi, in Paris 

 (twelfth century), one hundred and twenty-five skulls from the 

 Cimetiere des Innocents, used from the thirteenth to the eighteenth 

 century, and one hundred and twenty-five skulls from the old 

 Cimetiere de 1'Ouest, open from 1788 till 1824. 



Here are the results of this comparison, so far as regards the 

 mean capacity of the crania. 



Mean Capacity. 



Skulls of the twelfth century 84777 cubic inches 

 Cim. des Innocents 83783 

 Nineteenth century 86-901 



It will be seen that the mean capacity of the skulls belonging to 

 the present century possesses a decided superiority. As regards 

 the inferiority of the skulls from the Cimetiere des Innocents to 

 those of the twelfth century, Dr. Broca explains it by observing 

 that the crypts of the church of the 'Cite' were used by the 

 upper classes ; while as for the crania from Les Innocents, it is 

 beyond doubt that they belong to the lower classes, Philip 

 Augustus having presented that plot of ground to the city of 

 Paris as a burying place for the poor. 



Resting on these physiological data, Gall and his disciples, as 

 also Auguste Comte, Pritchard, and others in more recent times, 

 have held that the mental faculties are capable of augmentation, 

 inasmuch as they are transmissible. The conclusion appears 

 logical. Intelligence has for its condition, for its chief organ, the 

 brain ; the brain grows by exercise, and this growth is transmissible 

 by heredity. Hence it is perfectly fair to conclu4e that every 

 modification, every improvement of an organ, imports a modifica- 

 tion, an improvement in function, and that consequently the 

 development of the brain implies development of the intelligence. 



But this important fact, that progress of the intelligence is 

 possible, not only in the individual, but also in the race ; that 

 heredity transmits and accumulates trifling modifications, we 

 should wish to establish directly by psychological arguments, and 

 not by resorting to physiology, as we have just done. It is a 

 difficult task, and we can only attempt it 



We will first try to understand upon what condition the progress 



