SYSTEMIC AND SEX DETERMINANTS OF BONE 

 GROWTH (MUS NORVEGICUS ALBINUS). 



FREDERICK S. HAMMETT. 

 FROM THE WISTAR INSTITUTE OF ANATOMY AND BIOLOGY, PHILADELPHIA. 



Studies of the chemical differentiation of bone during growth 

 ('250, b, c] and a comparison of bone growth in length with that 

 in weight ('25^) indicated, as might be expected, that systemic 

 and sex factors are participants in the determination of the 

 mode and rate of development of this type of structure. It is 

 therefore pertinent to attempt an evaluation of the influence 

 of these factors in order that knowledge in this direction be 

 extended and rendered more precise. Such has been done for 

 the chemical differentiation and has been reported in the papers 

 cited. This paper deals with their evaluation in the growth of 

 the bones in weight and length. 



The raw data were obtained from the same source as that 

 which served for the previous studies, and hence are directly 

 related thereto. The material analyzed consisted of the lengths 

 and weights of the humerus and femur of male and female albino 

 rats 23, 30, 50, 65, 75, 100 and 150 days of age, together with the 

 respective body lengths and weights. The mean values and 

 their probable errors are given in Table I. 



The distribution of the material has been given ('250) and 

 need not be repeated. The animals were healthy. They came 

 from the Experimental Colony stock of the Wistar Institute, had 

 a common inheritance, and were raised under like conditions of 

 diet and environment as described by Greenman and Duhring 



('23). 



Data on the osseous system of the albino rat on age have been 



reported by Jackson and Lowery ('12) and Donaldson and 

 Conrow ('19). Their records do not lend themselves to an 

 analysis, such as the present, because of the lack of systemic or 

 sex separation. 



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