252 MORPHOLOGY OF THE CEREBRAL CONVOLUTIONS. 



convolution found on the mesial surface and which surrounds the corpus callosum in 

 the form of an ellipse. It is the only one to which he attributes a regular form. 

 The statements of these observers on the regularity of the cerebral convolutions 

 ware followed by Cuvier in regard to some other animals. According to him, "the 

 monkeys have much fewer convolutions than Man and among the Sapajous the 

 posterior lobe has scarcely any. In the Carnivora the fissures are also numerous 

 and they follow a certain order which is found the same in the greater number of 

 the species. The rodents have few or no sensible convolutions, but the ruminants 

 and the horses have many, as is also the case in the Dolphin. As regards the con- 

 volution in the brain of Man, Cuvier is content to say that they are the deepest of 

 all, but without recognizing in them any regularity." x 



Lanth 2 expresses about the same views. The observations of the Wenzel bro- 

 thers served to render the subject still more obscure. According to them, "with 

 Man the cerebral convolutions of one side differ from those of the other side in 

 form, direction, relation, seat, length and size. There is, however, on the internal 

 face of each hemisphere, immediately above the corpus callosum a convolution 

 almost symmetrical, but we find still marked differences between that of the right 

 and left side." 3 The inferior and posterior extremity of the convolution which sur- 

 rounds the corpus callosum, of which a part had been described by Malacarne and 

 admitted by the Wenzels, has been the object of special attention by Treviranus. 4 

 M. Serres, who gave to it the name lobe d' hippocampe, regards it in the same 

 manner as Treviranus ; and M. Lelut has investigated its structure. 5 



In 1816 Tiedemann G first gave a general account of the development of the con- 

 volutions and their times of appearance in the foetus. He did not. however, enter 

 into a comparison of the different convolutions. In his work 7 he has given some of 

 the most exact and best illustrations of brains published at that period. In it are 

 found representations of the brains of several monkeys, those of the seal, lion, cat, 

 coati, etc.; but with these also he has not entered into any description of the indi- 

 vidual convolutions. The work of Serres 8 although highly spoken of by Cuvier, 

 seems to have been retrograde in its tendency. It is full of inaccuracies and the 

 plates of the various brains figured seem to have been drawn almost hap-hazard. 

 From his researches Serres came to the conclusion that the characters of the con- 

 volutions were too inconstant to characterize species or families of mammals. He 

 divides animals into those which have convolutions similar, the one hemisphere to 

 the other, and those in Avhich they are dissimilar. In the first category he places 



1 Le9ons d Anatomie comp. 



2 Sur la structure du Cerveau. Journal complement. Paris., 1819. 



3 De penitiori struc'tura cerebri homines et brutorum. Tubingen, 1812. 



4 Recherches sur la struct, et les functions de l'enceph. des nerfs, etc. Trad, par M. Breschet, 1823. 



5 Note sur la substance blanche du lobule d'hippocampe, etc. Journal des Progres, 1830. 



6 Anatomie und Bildungsgeschichte des Gehirns im Foetus des Menschen. 



7 Sur les cerveau des singes et de quelques mammiferes rares dans nos contrees. 



8 Anatomie com paree, 1824-28. 



