i:: 



into line when viewed from this standpoint, and. no scientific reason existing in 

 the eontrarv. we may conclude tin- fact MS logically pio\en. Indeed, the gist of 

 tin- question is not win-tin i 'tin TI 'is a retlex centre in tlir spinal cc.nl fur the 



womb. Imt whether this centre produces tin- rhythmical expansion* and oontno- 



tions in that organ :is alleged. A full and sulVicicnt answer to this is fnmislicil 

 .11 the fact nf tlif total absorption of tin relative phenomena, :matomic;il and 

 physiological, w hieh otherw U,- are utterly inexjilicalile, underneath all which 

 :s the organic law on which animal life itself is constructed, railing for 

 rhythmical changes in pressure in the contents of the gravid womli and in the 

 uterine sinuses for increasing circul at ion. Nor is it reasonable that the enor- 

 nions nunil>er of muscles and nerves in the woml) are for compelling Otti the 

 cmiteiits at the end of the term simply. Imt, on the contrary, that they jH-rform 

 an active and essential part in the work of construction whirh ]>rci-edc8 expul- 

 sion, lieyond a shadow of a doiilit. they arc not idle in all this while. 

 :ally when supreme necessity would h:ive it otherwise; Oil the contrary, 



they an- n* /'</'- // for carrying on circulation, while at 



the end of the term they are available for insisting in expelling the embryo, 

 hence pe, form an active ;./< from the beginning to 'the end of their existence, 

 as is e\er the c;i.se with tin- miiM-les and nerves. 



( )nc oth'-r circumstance in tliis connection, namely, the very l<n-ln<ui course 

 of the arteries in the womb i Fig. C> i, which undoubtedly is adjustment with 

 this action, |K'rinittiiif; the rhythmical ex]iansions and contractions to take place 

 without involving any strain to the vessels. The veins, it will be perceived, taki > 

 a straight (Miu-sc, wliile the arteries are serpentine or ln>nt njvm themselves. 

 HUB is tine to the fact that the veins are more extensile, and possess greater 

 IMI-.VCI-S of elon^atiiiL,' and shortening than the arteries, the yellow elastic coat of 

 the latter tending to limit their actions. It will IK? remembered that this cir- 

 ciini.-t nice has forcible illustration in th" splenic artery and vein, the former 

 being almost twice- the length of the latter, to allow for expansion in the stomach 

 when fixxl is taken, otherwise this would involve prodigious strain to the vessels, 

 with great re luction of the calibre. But the same remark will apply to the ves- 

 sels of all the hollow viscera. Thus everything is in correspondence. Of course, 

 the arc of movement in the womb and placenta is necessarily more limited than 

 in the lungs, in 'which considerable space is required for sucking in the air 

 simultaneously with the venous blood, but which would not apply for the foetal 

 circulation, as the oxygen is furnished by art.-ri.'il blood at "/ ml the samr lini' 

 with the nutritive and force-producing elenvnts, which the scheme calls for in 

 order to generate force, since it is by a combination of the two that force is 

 evolved. The inclusion of the intestines with respiration by means of the 

 I meumogostric nerves has its explanation in this circumstance, as has been 

 fully set forth in the preceding pages. Differentiation in the organs 

 cannot, for obvious reasons, work any change in the fundamental principle 

 underlying the mechanics for increasing circulation, which is by rhythmical 

 changes in pressure involving a pumping action for compelling the commerce in 

 the bloodvessels and expelling waste products, while the speed of the currents 

 thus produced is determined by the rapidity and energy of the rhythmical ex- 



