256 MORPHOLOGY OF THE CEREBRAL CONVOLUTIONS. 



little attention, is very imperfect. To Gratiolet, however, is undoubtedly due the 

 credit of having first systematically mapped out the cerebral convolutions of the 

 Primates and of supplying a useful nomenclature. 



Foville in 1844 1 classifies the convolutions into four orders, according to their 

 arrangement around the anterior perforated space. This, however, has its appli- 

 cation only to the brain of Man. 



In Germany the subject of the cerebral convolutions has also attracted con- 

 siderable attention. Valentine in his studies of the Sommering doctrine of the 

 relations between the brain and nerves, attempted to find constancy in the convo- 

 lutions. In the best anatomical text books, however, such as Arnold, Meckel, 

 Hildebrand, Weber, Krause, Hyrtl and others, with the exception of a few easily 

 recognized constant ones, the convolutions are not considered or designated. Arnold, 

 in 1851, in his Anatomy, states that neither the direction of the convolutions 

 nor the divisions of the same have been studied, nor have any laws been discovered 

 governing their arrangement. 



Since then, Huschke, in 1854, 2 has attempted to lay down a plan on which the 

 convolutions are based. Bischoff, 1868, and Pansch, 1879, have also published 

 independent views on the morphology of the cerebral convolutions. Huschke, 

 through his studies in embryology and comparative anatomy, believed that in the 

 brain there are three or four ground convolutions which arch in the form of a horse- 

 shoe backward around the upper horizontal extremity of the fissure of Sylvius and 

 extend downward into the temporal lobe to the borders of the same. While these 

 ground convolutions are more or less distinctly recognizable in the brains of the 

 lower animals, in Man and the apes they are split by the development of the fissure 

 of Rolando or central fissure and its accompanying convolutions, the relations being 

 as follows : In the middle of the hemisphere we have the central fissure with its 

 accompanying convolutions. In front of this are three frontal convolutions, running 

 longitudinally, the first, second and third ; back of these there are likewise three 

 which run backward toward the end of the hemisphere, but only the upper two 

 reach the same, the lower running around the Sylvian fissure and extending into 

 the temporal lobe, which is also formed by the upper and middle convolutions after 

 they have reached the posterior end of the hemispheres proceeding forward. These 

 posterior convolutions coil themselves more than the frontal and form three upper 

 lobules : the lobulus parietalis superior or vorzwickel, the cuneus or zwickel and a 

 third, the end lobule, which forms the real point of the hemisphere. The middle 

 and lower convolutions which Huschke considers as one, show, according to 

 Bischoff, three lobules. On the inner surface of the posterior part of the hemi- 

 sphere, Huschke distinguishes the vorzwickel or precuneus and the zzvickel or 

 cuneus. On the lower surface the lobulus lingualis, Zungenlappchen, and one lying 

 more external, the spindel-formiges Lappchen or lobulus fusiformis, both of which 



1 " Traite complet de 1' Anatomie du systeme nerveux cerebro spinal." 



2 Schadel, Hein und Seele des Menschen und der Thiere, etc. 



