THE MAMMALIAN NERVOUS SYSTEM 47 



sect several spinal nerves of one side sufficiently to show the 

 spinal ganglia and the adjoining portions of the spinal nerve 

 trunks. 



43. Make a transverse section through the fetus in the tho- 

 racic region and construct a diagram magnified two or four 

 diameters to illustrate the relations of the spinal cord, spinal 

 nerves, spinal ganglia, and sympathetic ganglia, with their 

 peripheral connections, to the body wall as seen in the trans- 

 verse section. 



44. Spinal cord, gross structure. Note in the intact human 

 spinal cord (medulla spinalis) the following external features: 

 the size, shape, length, segmentation, the cervical and lumbar 

 enlargements (intumescentise), ventral and dorsal nerve roots, 

 ganglia, membranes (meninges), ligamentum denticulatum. 

 Determine the location of the four transverse sections of the 

 human cord which have been distributed. Review from the 

 text-books the anatomical formation of the spinal column, 

 the relations of the cord segments to their respective vertebrae 

 (Reid's chart), the blood-supply of the spinal cord, its method 

 of suspension in the vertebral canal, and, as far as possible, 

 the relations of the spinal nerve roots to their peripheral 

 distributions. 



Cunningham ('15), Figs. 459^65, pp. 517-522, and pp. 685- 

 753; Morris ('14), pp. 752, 756, 771-775, 914, 919-921, 964- 

 974; Quain ('09), Vol. Ill, Part 1, pp. 58-68; Vol. Ill, Part 2, 

 pp. 52-148; Piersol ('13), pp. 1021-1028, 1054, 1278, and the 

 following pages; Reference Handbook of the Medical Sciences, 

 3d ed., Vol. 7, article Spinal Cord; Sobotta ('11), pp. 114-124; 

 Spalteholz ('09), Vol. Ill, pp. 617-623; Toldt ( r 04), pp. 752- 

 759 and 810, ff. 



45. Brain membranes. Each student should be supplied if 

 possible with a sheep's brain and one lateral half of a human 

 brain. The intact human brain will first be examined by two 

 students at adjacent desks before being cut into halves. 



Study the brain membranes (meninges) and blood supply of 

 the sheep's brain, especially the circle of Willis (cf. Burkholder, 

 ('12), Plate IV) and the other vessels of the ventral surface, 

 and compare with the human. Review from the reference 

 books the form of the human skull and its foramina with their 



