NO. 3 COMPARATIVE HISTOLOGY OF FEMUR FOOTE 185 



FEMUR OF A WHITE MALE. NO. 53, CR. MED. COLL. 



Pl. 29, Fig. 375. Syn. Tab. X 



Antero-posterior diameter of bone, 28 mm.; lateral, 30 mm. 



Antero-posterior diameter of medullary eamd, Ki mm.; lateral, 17 mm. 



Cancellous bone surrounds the medullary canal and is most prominent in 

 the anterior wall. The medullary canal is full. Medullary index, 48%. 



Structure. — The external circumferential lamella; surround the bone at 

 scattered intervals. Their lacunae are long and narrow and their canaliculi 

 are long. The central ring, constituting nearly the entire thickness of the wall 

 of the bone, is composed of Haversian systems, which, in places, form the 

 external boundary of the bone. At some points in the periphery, only half or 

 three-quarter systems appear directly under the periosteum. The systems vary 

 in size, but are highly developed. Their lacuna; are long and narrow and their 

 canaliculi are long. The Haversian canals intercommunicate. The internal 

 circumferential lamellae surround the medullary canal in the form of cancellous 

 bone. 



Type III, C. 



RIGHT FEMUR OF A WHITE M.ALE. NO. 171, MED. DEPT. NORTHWESTERN UNIV. 



Pl. 29. Fig. 376. Syn. Tab. X 



Antero-posterior diameter of bone, 30 mm. ; lateral, 33 mm. 



Antero-posterior diameter of medullary canal, 17 mm.; lateral, 15 mm. 



The medullary canal is full. JMedullary index, 35%. 



Structure. — The external circumferential lamellae appear in fragments. 



The section is composed almost entirely of Haversian systems with very 

 little inter-Haversian lamellar structure. The systems vary in size and some 

 of them show senile changes. 



The internal circumferential lamella; form a very narrow ring around the 

 nledullary-^canal. The bone is high in development, since practically all lamellar 

 and laminar formations have disappeared and Haversian systems have taken 

 their places. It shows, liowever, senile changes. 



Type III, C, senile. 



LEFT FEMUR OF A WHITE MAN. NO. 95, CR. MED. COLL. 



Pl. 39, Pig. 377. Syn. Tab. X 



Antero-posterior diameter of bone, 30 mm. ; lateral, 27.5 mm. 

 Antero-posterior diameter of medullary canal, 17 mm.; lateral, 16 mm. 

 The medullary canal is full. Medullary index, 42%. 



