46 LABORATORY OUTLINE OF NEUROLOGY 



('18), chapters XIII, XIV, XV. On the cerebro-spinal fluid, see 

 Halliburton ('16); Weed ('14). 



46. Surface anatomy of the brain. — With the intact human 

 brain and the sheep's brain before you, examine and compare 

 their external forms. Now compare both of these brains with 

 that of the dogfish. Identify in each brain the chief subdivisions 

 referred to in Section 38, so far as these are visible from the sur- 

 face. After the brain has been cut in two, as directed in Section 

 58, some of these subdivisions will be more clearly seen. In 



vermis 



\trap. 



Fig. 7. — The brain of the sheep seen from the right side. Natural size. 

 b.ol., olfactory bulb; f.lat., fissura lateralis (Sylvii); floe, flocculus; f.rh., 

 fissura rhinalis; g.f.i., gyrus frontalis inferior; g.orb., gyrus orbitalis; II to 

 XII, cranial nerves; lob.pir., lobus piriformis (gyrus hippocampi); n.ol.l., 

 nucleus olfactorius lateralis; pfl., paraflocculus; trap., corrjus trapezoideum. 



what parts of the brain do you find the greatest resemblances in 

 the three species; where the greatest differences? 



Learn the names of the larger structures visible upon the 

 surface of the brain, omitting the minor subdivisions of the 

 cerebellum and (for the present) the sulci and gyri of the cere- 

 bral cortex, for the study of which see Sections 114 and 115. 



On the brain of the sheep see Figs. 7 to 12, and for additional 

 illustrations consult Burkholder ('12) and Fiske ('13); for the 

 human brain consult any standard text-books. 



47. The cranial nerves. — (a) Locate on both the sheep and the 

 human brains the roots of the twelve pairs of cranial nerves. 



