MORPHOLOGY OF THE CEREBRAL CONVOLUTIONS. 251 



systematic morphological theory which shall explain the arrangement of all the 

 fissures of the cerebral surface as related to a distinct plan, dependent upon the 

 structure and mode of development of the hemisphere itself, together with the dis- 

 turbances and departures due to the action and interference of the bony environ- 

 ment. 



GENERAL HISTORY. 



Amongst the earliest writers on the subject of the cerebral convolutions was 

 Erisostratus, who affirmed that they were more numerous in Man than in the 

 lower animals, and he was of the opinion that the superior intelligence of Man is 

 associated with this fact. Penault notices the convolutions as found in the mon- 

 keys, and says that they closely resemble those of Man, but does not describe them. 

 Willis, however, was the founder of the comparative anatomy of the convolutions. 

 He pointed out in 1664 1 the presence of the convolutions in the brains of the lower 

 animals. He asserts that they are not so numerous as in Man, and that the ape 

 possesses more of them than the fox, dog, etc., and he affirmed that paucity was 

 associated with simplicity of folding. In 1789, Vicq d'Azyr 2 devoted some attention 

 to this subject. He remarks that in the monkeys, as in quadrupeds in general, the 

 convolutions are less numerous, symmetrical on the two sides and are related to 

 each other in all. individuals of the same genus, but that in Man they are neither 

 symmetrical on the two sides nor resemble each other in different individuals. He 

 was among the first to recognize similarity of plan in Man and the monkey. He 

 was also the first to point out certain fissures as being constant and he recognized 

 the Sylvian and calloso-marginal as such. The plates that illustrate his work, 

 however, are so inaccurate that they seem to be drawn almost at random and are 

 of no value for study. In 1751, Tyson 3 had compared the brain of an 

 Orang with that of Man and stated that they strongly resembled one another, but 

 did not enter into any detailed description of either. Soemmering describes in his 

 Nervenlehre, together with Th. Bartolinus, the formation, of sulci and gyri and con- 

 siders them only as a means of deeper penetration of the .membranes of the brain. 

 He gives them no further consideration except that he says they might seem at 

 first glance to be irregular, but that taken in groups they are always very regular. 

 In his " de Basi Encephali, scriptores nevrologici minores," he has been more exact 

 than any of his predecessors in the reproduction of several of the cerebral convolu- 

 tions of Man ; but that he had not given the subject sufficient attention is shown 

 by the fact that he speaks highly of the very inaccurate plates given by Vicq 

 d'Azyr. 



Malcarne in 1795 4 in describing the brain of a goat notices particularly a 



1 Cerebri Anatome, etc. 



2 Encyclopgdie method., Syst. Anat. 



3 The anatomy of a Pygmy compared with that of a Monkey, an Ape and a Man. London, 4to. 



4 Encefalotomia di alcuni Quadrupedi, etc. 



