ANIMAL MECHANICS. 



31 



The portion of the deltoid employed, as found from the 

 means, is ^Vfth of the whole; so that, combining all the 

 foregoing results together, it is very probable that the weight 

 of deltoid used in holding the arm horizontal is J§ths of the 

 whole weight of the muscle. 



If the muscle be divided into a clavicular, an acromial, 

 and a scapular portion, the portion used in holding the arm 

 horizontal is very nearly Jths of that taking origin from the 

 whole tip and line of the acromion ; but for the purpose of 

 future experiments it may be found easier to weigh the whole 

 muscle, and take -J§ths of that weight, than to separate it into 

 its parts by direct dissection. The mean weight of the por- 

 tion of the deltoid engaged in holding the arm in the hori- 

 zontal position has been found to be 2.83 oz. av. ; and to 

 this must be added the mean weight of the supraspinous, 

 which may be found as follows : — 



Table IV. — Weight of Supraspinous Muscle. 



A. Female, 



B. Male, 



C. Male, 



D. Male, 



E. Male, 

 P. K. Male, 



1 .01 oz. av. 

 1.76 „ 

 2.18 „ 

 i-75 „ 

 °-93 „ 

 2.40 „ 



Mean, . . 1-671 oz. av. 



This result is almost identical with that found in Table III., 

 from four well-developed dead subjects. This result of Table 

 IV. is interesting from the fact that it contains the actual 

 weight of the supraspinatus, observed 40 minutes after death, 

 in a criminal (P. K.) executed, by hanging, for murder. As I 

 shall have occasion to refer to this case for other purposes, I 

 here give the data, as observed by myself : — 



