ANATOMY IN A NUTSHELL. 



365 



CXCIX) the secondary center in the uncinate gyrus of the temporal lobe 



on the mesial surface. (Plate CLXXXII). This has been demonstrated 

 by experiments upon animals and by pathological research on the brain of man. 

 In osmatic animals these lobes (gyrus hypoeampus, uncinate, and hippocampus 

 major) where the center of smell is located, are well defined. In anosmatic 

 they aresmall. If the olfactory tract be removed these lobes will atrophy and in 

 case of lesion in these lobes the loss of smell (anosmia) will follow. The ol- 

 factory tracts, which are white, lie almost parallel to one another, extending 

 from the under surface of the frontal lobe. The bulb is reddish-gray in color 

 and lies on the cribriform plate of the ethmoid. From the bottom of these bulbs the 

 olfactory nerves are given off, twenty or thirty in number, to be distributed to 

 the cells of Schultze in the Schneiderian membraxk. The three roots 

 from the tracts are the external, middle, and internal. The external root 



PLATE CLXXXV. 



Showing Long and Short Association Fibers of the Brain. 



is white and extends into the anterior end of the hippocampus gyrus of the tem- 

 poro-sphenoidal lobe. The middle one is gray and ends in the trigonum ol- 

 factorium. The inner one, or mesial hoot, is white and passes backward and 

 inward to end in the anterior extremity of the gyrus fornicatus. The mesial 

 root is continuous with one end of the limbic lobe and the external root with 

 the other. This nerve is made up exclusively of non-medullated fibers. They 

 are deficient in the white substance of S< hwann and consist of axis-cylinders with 

 a distant nucleated sheath in which there are, however, fewer nuclei than in the 

 ordinary non-medullated fibers. 



1. Anosmia is the loss of smell. 



2. Hyperosmia is increased sensitiveness. 



3. Parosmia is perversion of the Function of smell. 



4. Kakosmia is a condition where everything smells alike to the patient and 

 the odor is a peculiar or offensive one. 



