MANNER OF DEVELOPMENT. 61 



noptera these ganglia are many times larger than in the 

 less intelligent orders, such as beetles.* On the other 

 hand, no one supposes that the intellect of any two ani- 

 mals or of any two men can be accurately gauged by the 

 cubic contents of their skulls. It is certain that there 

 may be extraordinary mental activity with an extremely 

 small absolute mass of nervous matter: thus the wonder- 

 fully diversified instincts, mental powers and affections of 

 ants are notorious, yet their cerebral ganglia are not so 

 large as the quarter of a small pin^s head. Under this 

 point of view the brain pf an ant is one of the most mar- 

 velous atoms of matter in the w^orld, perhaps more so than 

 the brain of a man. 



The belief that there exists in man some close relation 

 between the size of the brain and the development of the 

 intellectual faculties is supported by the comparison of the 

 skulls of savage and civilized races, of ancient and modern 

 people, and by the analogy of the whole vertebrate series. 

 Dr. J. Barnard Davis has proved,! by many careful meas- 

 urements, that the mean internal capacity of the skull in 

 Europeans is 92.3 cubic inches; in Americans 87.5; in 

 Asiatics 87.1; and in Australians only 81.9 cubic inches. 

 Professor Broca X found that the nineteenth century 

 skulls from graves in Paris were larger than those from 

 vaults of the twelfth century, in the proportion of 1484 to 

 1426; and that the increased size, as ascertained by meas- 

 urements, was exclusively in the frontal part of the skull 

 the seat of the intellectual faculties. Prichard is per- 

 suaded that the present inhabitants of Britain have 

 ^^ much more capacious brain-cases " than the ancient in- 

 habitants. Nevertheless, it must be admitted that some 

 skulls of very high antiquity, such as the famous one of 

 Keanderthal, are well developed and capacious. AVith 



*Dujardin, " Annales des Sc. Nat.," 3d series Zoolog. torn, xiv, 

 1850, p. 203. See also Mr. Lowne, ' ' Anatomy and Phvs. of the 

 Musca xomitoria" 1870, p. 14. My son, Mr. F, Darwin, dissected 

 for me the cerebral ganglia of tlie Formica rufa. 



t " Philosophical Transactions," 1869, p. 513. 



X " Les Selections," M. P. Broca, " Revue d'Anthropologies," 1873 ; 

 see also, as quoted in C. Vogt's " Lectures on Man," Eng. translat., 

 1864, pp. 88, 90. Prichard, " Phys. Hist, of Mankind," vol. i, 1838, 

 p. 305. 



In the interesting article just referred to. Prof. Broca has well 

 remarked, that in civilized nations, the average capacity of the skull 



