THE SPLENIC CIRCULATION. 163 



By the use of the above instrument Schafer and Moore found — 



1. That the spleen volume is extremely responsive to all fluctuations 

 in the general blood pressure, and not independent of these, as had been 

 supposed by Eoy. 



2. That when the nerves going to the organ are intact, other 

 fluctuations in the volume of the spleen may occur, which exactly 

 correspond to Traube-Hering curves of arterial pressure. On the 

 other hand, these fluctuations of volume may not correspond, and 

 the arterial curve may be rising while the splenic is falling. In the 

 first case, the variations in splenic volume are purely passive, and follow 

 the rise and fall of arterial pressure. In the second case, the spleen- 

 arterioles, like those of the kidney, share in the general rhythm of con- 

 tractility, contracting when the arterioles contract, and expanding when 

 the arterioles generally dilate. 



3. That the specific rhythmic variations in splenic volume are 

 almost entirely abolished by chloroform. 



4. That rhythmic contraction and dilatation occur in the spleen 

 when excised and fed by an artificial circulation of defibrinated blood. 



Sv<y Spleen. . /^S 



Carotid 



xAA/VVVV 



Dog. 8.5 kilo. All connections with spleen severed except 



one artery, vein, and. the accompany ingr nerves. 

 O Pressure 



Seconds 



TrrrrrirrinnrFrinrrruTuiTTiruTinrrrirT^ 



Fig. 100. — Aortic pressure and splenic volume. 1 — Schafer and Moore. 



These movements may therefore be carried out quite independently of 

 the central nervous system. 



5. That certain conditions, such as diminution of oxygen in 

 the blood, produce not only a general contraction of the organ, 

 but also a subsequent increase in the extent of its rhythmic move- 

 ment. Extract of suprarenal gland produces an extreme condition of 

 contraction. 



6. That certain drugs, such as curari, or a watery extract of dried 

 brain, greatly increase the contractions of the spleen. Anaemia of the 

 organ acts in the same way, whether produced by compression of the 

 artery, or otherwise. 



The innervation of the spleen was first investigated by Bulgak, 2 and 

 has recently been worked out more fully by Schafer and Moore. 

 Bulgak observed the spleen directly, and described the nerves in the 

 gastro -splenic omentum as of two kinds, afferent and efferent. Stimula- 

 tion of the peripheral end of the efferent fibres caused marked contrac- 

 tion of the spleen. The organ became pale in colour, its edges rounded, 

 and its surface crinkled. Excitation of the central end of the afferent 

 nerves produced well-marked reflex contraction of the organ. Bulgak 



1 The line of zero blood-pressure should be placed some millimetres lower. 

 3 Bulgak, Firchow's Archiv, 1877, Bd. lxix. S. 181. 



