98 CARNEGIE INSTITUTION OF WASHINGTON. 



attachment is an important point in topographical anatomy and 

 musculo-mechanics, and is of no less interest to the anthropologist. 

 Dr. Schiiltz studied the insertion of the two muscles in both the right 

 and left humerus in white and negro cadavers. The measurements 

 were taken projectively and expressed in percentages of the absolute 

 lengths of the humeri. From these were obtained indices of position, 

 standard deviation, and variation coefficients, which show the possi- 

 bilities of variation in the insertion of the two muscles. The deltoid 

 possesses a more constant position of insertion than the pectoralis 

 major muscle. No racial difference was observed, but the insertions 

 showed a marked difference in the sexes, the pectorahs major being 

 more proximally attached in the female. Asymmetries are surprisingly 

 common, and individuals with an exactly equal position of muscle 

 insertion on the two sides may be considered as exceptions. 



In this connection it may be mentioned that the Zurich inaugural 

 dissertation of Dr. Schultz on anthropological studies on the base of 

 the skull has come from press during the past year. 



In the last report the work of Dr. John C. Koch on the laws of 

 bone architecture was referred to, and since then this has been extended 

 to a study of the distribution of fractures of the femur in a series of 

 cases treated at the Johns Hopkins Hospital. It was found that the 

 actual distribution is in close agreement with the theoretical, as 

 calculated from a mathematical analysis of the architecture of the 

 normal human femur, and that the tendency to fracture at any point 

 varies inversely as the least strength in that segment. 



Dr. C. C. MackHn has completed his study on experimental cal- 

 cification of tissues in madder-fed animals, an account of which was 

 given in the last report, and his paper has now appeared in its final 

 form. As a somewhat related subject Dr. Macklin has studied also 

 the formation of callus in the process of bone repair in rats vitally 

 stained with trypan blue. He finds that following the first inflamma- 

 tory reaction macrophages congregate in great numbers at the site 

 of the injury, being most active from the third to the sixth day, at 

 which time they begin to undergo disintegration. During the removal 

 of the callus, from the tenth to the twentieth day, other cells derived 

 from its spaces, and resembling macrophages of developing bone, 

 show a marked reaction to the vital dye, thus manifesting their 

 phagocytic activity. A preliminary account of this work has appeared 

 and the completed paper is now in press. 



The preceding report from this department contained an account of 

 two papers published by me regarding the histogenesis of the con- 

 nective tissue and cartilaginous coverings of the membranous laby- 

 rinth. This study has been extended and has since appeared in 

 completed form as one of the papers in Publication No. 227 of the 

 Carnegie Institution of Washington. 



