I 
THE CRANIAL NERVES AND SPECIAL SENSE ORGANS QI 
the yellow tarsal glands, connected with the roots of the eyelashes, 
may be seen; the moist condition of the conjunctiva is due to the 
lacrimal secretion which reaches the surface of the conjunctiva 
through orifices of ductules above the lateral angle and is drained 
off through the orifices of the naso-lacrimal duct, which are located 
on the lacrimal papillae upon the eyelids above and below the 
medial angle. In this region also, look for the semilunar fold of 
conjunctiva (the nictitating membrane) and the lacrimal caruncle 
medial to it. Draw the eye with its surroundings as seen from the 
front. 
Examine the various optical models of the eye which demon¬ 
strate the method of formation of the Image of an object upon the 
retina, and the range of accommodation for vision of objects at 
varying distances. 
D. THE OLFACTORY ORGAN AND ITS ACCESSORIES. 
For this work students may group themselves in pairs, each 
pair being supplied with (i) a whole head from which the brain 
has been removed, and (2) a head which has been sawn as above 
directed in a median sagittal plane. The nasal region of the first 
should be sawn in a series of parallel transverse sections at right 
angles to the long axis of the nose and about 1}^ inches apart. 
In so doing be careful not to injure the tongue. Wash the sawn 
surfaces under running water to remove debris. In the case of 
the half heads, if the nasal septum is still in place, remove it, 
carefully noting what parts are of connective tissue, and of carti¬ 
lage, and identifying the bones which contribute to it. Make a 
careful study and comparison of these preparations, using each 
point of view as a means for identifying the structures which 
appear in the other one. Note the following points: extent and 
boundaries of the nasal cavities; nature of lining mucous mem¬ 
brane and devices for increasing its area; division of cavity into 
pars olfactoria, and pars respiratoria; the cribriform plate of the 
ethmoid, through the numerous fenestrae of which the fiber bun¬ 
dles of the olfactory nerves pass to reach the mucous membrane 
of the pars olfactoria of the nasal cavity; the conchae, with their 
supporting bony framework of the scroll-like maxillo-turbinal, 
maso-turbinal, and ethmo-turbinal bones. 
