258 



Rev. S. Haughton on the 



[Mar. 10, 



hydrostatical pressure only, and is therefore easily measured, and the sup- 

 position of spherical curvature is approximately admissible. 



It is evident from the form of the gravid uterus, that its curvature is 

 greatest near its mouth ; and the equation shows that for a given hydro- 

 statical pressure the tensile strain is proportional to the radius of curvature ; 

 hence this strain will be greatest at the fundus of the uterus, in which 

 part, accordingly, we find the muscular coat thicker than elsewhere. If 

 we assume the shape of the uterus to be that of a prolate ellipsoid, whose 

 longer diameter is 12 inches, and shorter diameter 8 inches, its mean cur- 

 vature will be that of a sphere whose diameter is 9*158 inches. 



The volume of the gravid uterus is found from the expression 



4 



Volume = - nab 2 ; 



in which a and b are the semiaxes, and ir is the ratio of the circumference 

 of a circle to its diameter ; substituting for a and b their numerical values, 

 we find the contents of the uterus to be 402*13 cubic inches. 



The surface of the gravid uterus may be found from the equation 



Surface = ? ^ a ^ (sin" 1 ^ + e V\ _ e -) ; 

 e 



in which e is the excentricity of the generating ellipse. If the numerical 

 values be substituted in this expression, it will be found that the surface 

 of the uterus is 2/0*66 square inches *. 



Some highly interesting conclusions may be drawn from the preceding 

 calculations, combined with the weight of the total muscular tissue of the 

 uterus. Heschl estimates the weight of the uterine muscles at from 1 lb. 

 to 1*5 lb., Montgomery found the muscles of the gravid uterus to weigh 

 1*5 lb., and Levret estimates them at 51 cubic inches, which, with a specific 

 gravity of T 05 2, I find to be equivalent to 1*93 lb. Taking the mean of 

 these estimates we have : — 



Weight of Muscular Fibres of Gravid Womb. 



lbs. 



Heschl , 1*25 



Montgomery 1*50 



Levret ... 1*93 



Mean 1*56 



If we now suppose this quantity of muscle to be spread over the entire 

 surface of the uterus, we find 



Mean thickness of muscu- J 1-56x7000x 1000 1 —0*1519 inch 

 lar wall of uterus \ 252-5x270*66x 1052 J ~~ mC ' 



* Levret estimates the contents of the gravid uterus at 408 cubic inches, and its 

 surface at 339 square inches. 



Poppel estimates the contents at 300 cubic inches, and the surface at 210 square 

 inches. 



