150 ANTHROPOLOGY. 



substance called fat. In tLe cellular or areolar tissue, on tlie other hand, we 

 have numerous bands or threads of white librous tissue crossing each other, 

 and leaving interstices which communicate freely. The two tissues are 

 usually associated together, the adipose being inclosed in the meshes of the 

 areolar, but in some situations, as in the medullary canal of the long bones 

 (where it is known as the marrow), in the omenta, along the mesenteric 

 vessels, and upon the heart, the adipose tissue may be abundant, with Httle 

 or no cellular. 



Adipose tissue consists of two distinct elements, the secreting membrane 

 and the secreted product. The former consists of fine transparent mem- 

 branous cells surrounded by capillaries ; each sac is somewhat round, but 

 by aggregation and consequent compression is made to assume various 

 figures. The vessels pass in the interstices between the cells, and surround 

 each by a delicate inosculation. The adeps or fat, which occupies each 

 cell, is a soft, yellowish, oily substance, presenting a great variety with the 

 individual. In youth it is most abundant towards the exterior, the reverse 

 existing in old age. The fat contributes to the covering of the body, and 

 being a bad conductor of heat, assists in retaining its temperature ; by fill- 

 ing up numerous interstices, it adds to the compactness and symmetry of 

 the system ; it may also serve as a reservoir of nutritive materials from 

 which the system may derive an occasional supply. 



PI. 129, fig. 24, vertical section of the skin showing its microscopical 

 structure : ', epidermis with its undulating lines; ", sudoriferous gland and 

 canal; ', cutis vera; \ apparatus for secreting pigment substance; ', seba- 

 ceous gland with its duct ; *■ ", papiU» ; ', blood-vessels of the skin. Fig. 

 25, vertical section of the thumb to exhibit the insertion of the nail : \ nail ; 

 '•', continuation of the cuticle ; ', cutis vera ; ' (left hand side), adipose tis- 

 sue ; ', fold of skin containing the root of the nail ; ", section of the terminal 

 bone of the thumb. Fig. 26, body of the thumb nail : ', lateral fold ; 

 '\ ridges caused by the linear rows of papillse on the subjacent cutis vera ; 

 ', lunula or spot at the base of the nail. 



2. Anatomy of the Nose, or Organ of Smell. 



The nose is situated between the orbits, above the mouth and glottis, 

 and in front of the pharynx and of each tympanum, communicating with 

 all these regions. Though median in position it is really a double organ, 

 being completely divided by a partition or septum into two symmetrical 

 portions, called the nares or nasal fossae. The nasal passages have a two- 

 fold use : they constitute the organ of smell, the olfactory nerve being dis- 

 tributed to the vascular membrane covering their irregular and convoluted 

 aspect ; and 'secondly, they serve as avenues to the respiratory organs. 

 We may conveniently examine the nose as composed of two portions : the 

 one, anterior or external (the nose proper), consisting of cartilages and soft 

 parts ; the other, posterior or internal, the nares or nasal fossae, composed 

 of bones covered by highly vascular mucous membrane. 

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