70 [August, 1841. 



growth no longer existed, from the final cessation of enlargement 

 in the brain. Uniting with Dr. Morton in the belief that the office 

 of the sutures was to permit a more rapid development and 

 growth of the cranium, by allowing ossification to go on from 

 several centres at the same time, the bones of the skull, in this 

 respect, resembling the trunk and epiphyses of a long bone, Dr. 

 Coates inclined, at the same time, to the double belief that growth 

 and other changes took place, not at the sutures only, but through- 

 out the whole extent of a living cranial bone. The parietal bone 

 of a newly born infant was not mathematically of the same shape 

 with the central portion of that of an adult. Were the brain, in 

 one of the cases referred to by Dr. Morton, to acquire, by any 

 means, a further enlargement, it ought to be presumed, in the 

 present state of our physiological knowledge, that the bone would 

 enlarge to a corresponding extent ; and it would be therefore, in- 

 ferred that the ossification of the sutures would not limit the 

 growth of the brain. 



This view Dr. Coates endeavoured to illustrate by a comparison 

 with the opinion of Mr. Serres, that the relative and successive 

 growth of the parts of the brain were a consequence of the relative 

 size of their arteries during the period of formation ; in regard to 

 which, he believed, physiologists were much agreed in the con- 

 clusion that the developement of a portion of the brain and of its 

 corresponding artery were coetaneous processes ; but that if any 

 priority in causation were to be allowed, it should be assigned to 

 the organ ; in consequence of the existence and comparative size 

 in outline of which, it became necessary, if the ability of the sys- 

 tem permitted, that a proportionate supply of blood should be 

 furnished to the part, through a vessel of a suitable size, in order 

 to aflbrd new materials for enlargement. Primary growth, he 

 imagined, took place in the interstitial substance, and that the 

 larger arterial branches, and even the capillaries were rather an 

 instrument or adjuvant than a cause. The formation of additions 

 to existing solids would thus resemble that of the primordiaof the 

 foetus, near which no vessels of the parent are observed, while the 

 vascular appearances are found to approach the newly organized 

 individual at a period subsequent to its formation. 



