NO. 3 COMPARATIVE HISTOLOGY OF FEMUR FOOTS 199 



LEFT FEMUR OF A WHITE MALE. NO. 152, MED. DEPT. NORTHWESTERN UNIV. 



Pl. 33, Fig. 412. Syn. Tab. XI 



Antero-posterior diameter of bone, 216 mm. ; lateral, 37 mm. 



Anteroposterior diameter of medullary canal, 14 mm.; lateral, 16 mm. 



The medullary canal is full. Medullary index, 30%. 



Structure. — The section is the first portion of a double femur. The original 

 femur (fig. 412B) is composed of Haversian systems almost entirely. In the 

 posterior wall they are separated by short lamellae with oval lacunje. Many 

 senile changes occur. In some systems the Haversian canals have increased 

 in diameter to such an extent that only a narrow rim of bone remains. Around 

 the medullary canal are large spaces. The lacunas of the systems are of the 

 oval type and not very numerous. The external and internal circumferential 

 lamellae appear in fragments. Between the original and accessory growth is 

 a concentric series of spaces partly surrounded by enclosing lamellae. A sharp 

 line ajjpears between the two bones (fig. 412C). The accessory bone is com- 

 posed of a background of lamellfe in which are Haversian systems of the (lb) 

 differentiation and numerous radiating canals. The inter-Haversian lamellas 

 with oval lacunai predominate. Many of the systems are senile. The external 

 circumferential lamellae are fragmentary. The accessory portion shows an 

 earlier development than the original bone by its predominating lamellae and 

 relatively few Haversian systems. 



Type I-III, lb, C, senile. 



LEFT FEMUR OF A WHITE MALE. NO. 152, MED. DEPT. NORTHWESTERN UNIV. 



Pl. 33, Fig. 413. Syn. Tab. XI 



Antero-posterior diameter of original bone, 27 mm. ; lateral, 25 mm. 



Antero-posterior diameter of medullary canal of original bone, 16 mm.; 

 lateral, 17 mm. 



The medullary canal is full. Medullary index, 67%. 



Antero-posterior diameter of accessory bone, 23 mm.; lateral, 18 mm. 



Antero-posterior diameter of accessory medullary canal, 10 mm.; lateral, 

 10 mm. 



The medullary canal is full. Medullary index, 31%. 



Antero-posterior diameter of the whole bone, 25 mm. ; lateral, 45 mm. 



The section was taken 33 mm. below figure 412. 



Structure.— In this section the accessory development has formed an addi- 

 tional femur. The original bone is composed of Haversian systems for the 

 most part, but their senile changes are markedly increased (fig. 413B). The 

 accessory bone is composed of lamellae with oval lacunae, interrupted by numer- 



14 



