FAT —MUSCLES —BLOOD VESSELS 



55 



Adipose tissue. Representing the so-called hibernating gland, 

 multiocular fat masses are found in the rat (Rasmussen, '23) in 

 all of the localities where they have been described, namely: 

 in the cervical, scapular, axillary, thoracic, renal and inguinal 

 regions. The proportion of fat (boiling alcohol extract) has 

 been determined by Hatai ('17) in a series from birth to matur- 

 ity (see table 166). 



TABLE 20 



Naso-occipital length 



Interzygomatic width* , 



Upper diastema 



Upper incisor — total length. ... 

 Upper incisor- — extra-alveolar 



length 



Lower diastema 



Lower incisor- — total length. ... 

 Lower incisor- — extra-alveolar 



length 



46.5 

 15.5 

 13 

 26.2 



9.3 



6.8 



31.3 



12.4 



*Same as 'squamosal distance', figure 1, p. 51. 



TABLE 21 



Newborn 



15 days 



16 days (very well grown) 

 30 days 



420 days 



NUMBER OP 

 MUSCLE FIBERS 



5919 

 7252 



7587 

 7625 

 8014 



NU.MBER OF NUCLEI 

 PER CUBIC MM. 



570645 

 357764 

 347343 

 139861 

 37542 



AREA OF CROSS 



SECTION IN 

 MM. X 37 DIAM. 



552 



868 



1010 



2766 



11817 



4. Muscles. Morpurgo ('98) has furnished data on the Muse, 

 radialis of the albino rat; giving the number of muscle fibers 

 and of nuclei at different ages (table 21). 



5. Blood vessels and lymphatics. Blood vessels. Using six 

 groups of rats, those of each group being similar in body weight, 

 but neglecting sex, Dreyer, Ray and Walker ('12) have deter- 

 mined the relation of the area of the cross-section of the aorta 

 (in mm.) to the area of the surface of the body and to the body 



