Dwight.] J-J-O [March 17, 



Second Seriics. 



150 MALE. 150 FKMALE. 300 OF BOTH SEXES. 



Present on both sides 70^4(5.6% 59 = 39.3% 129 = 43% 



Present on neither side 56 = 37.3 69 = 46 125 = 41.6 



Present on right side ^ -i ^ 



"""^ ^1 i.24=16.1 l*^ 1.22=14.7 ^^\iQ = l5A 



Present on left side i i 



only 13 ^ 13 ^ 25^ 



The percentages are so nearly alike that there is no occasion to combine 

 the series. The subjects came from all parts of Russia, and were mostly 

 Sclaves. The following results are self-evident : 1. That, at least on one 

 side, the muscle is more frequently present than wanting, although in 

 more than half the cases it is wauling on at least one side. 2. That it is 

 more common in man than woman. 3. That the two sides are alike very 

 much more often than unlike. This is directly contradictory of Ilallet's 

 results. 4. That practically it is found asofien on one side as on the other. 



Since this paper was first read the report of the Committee of Collective 

 Investigation of the Anatomical Society of Great Britain and Ireland has 

 appeared.* It shows that 457 bodies were examined and that the muscle 

 was wanting in 270 (59 per cent.), that it was present on both sides in 139 

 (30 per cent.), on one side in 48 (11 per cent.). It was found only on the 

 right side 27 times against 21 on the left. It was therefure more often 

 wanting than present. The sex was stated only in 171 instances. Both 

 muscles were wanting in 54 per cent, of the males, and in 65 per cent, of 

 the females. 



The observations about to be reported were made at the Harvard Medi- 

 cal School. Those on negroes are not included in any series. As it often 

 happened that the observation on one side of a subject had been neglected, 

 or for some reason had to be discarded, I give first a series of observations 

 in which only the number of sides of bodies is considered. It comprises 

 608 sides, divided into 299 right sides and 309 left sides, and also by the 

 sexes. It shows that considering sides only, the muscle is more often 

 wanting than present ; that it is more common in man than in woman, and 

 that there is little difierence between the sides. 



Frequence op Psoas Parvus in 608 Sides. 



RIGHT. LEFT. TOTAL. 



Male Present 89 8S 177 



Wanting 102 121 223 



Total 191 209 400 



Per Cunt, present 4G.5 42.1 44.2 



* Journal of Anat. and Pliys., Vol. xxvii, January, 1S93. 



