Franklin P. Mall 327 
fishes unless the muscles of the trabeculae and capsule are paralyzed 
or are thrown out in some way. Jaschkowitz” found by cutting the 
nerves of the spleen that the muscle becomes paralyzed and the pulp fills 
with blood. I have repeated Jaschkowitz’s experiment and have discussed 
it more fully elsewhere.” It appears to me that in view of the anatomy 
of the spleen and the effect of contraction of the muscle upon blood in 
the pulp it is rational to conclude that when the muscle is paralyzed by 
cutting the nerves the increased amount of blood in the pulp came directly 
from the arteries rather than back through the veins. The muscle “is 
excluded and we have-on one hand high arterial pressure and on the 
other hand low venous pressure. It appears to me that there is but one 
way by which this blood got into the pulp-spaces, i. e., through the holes 
in the ampuliae. 
In connection with the effect of contraction and. relaxation of the 
muscle of the spleen and its effect upon the blood in the pulp we may 
consider Roy’s * discovery of its rhythmic contraction. It was found that 
the contractions of the spleen are very regular, one a minute, and that 
the change of volume during each contraction may be as much as 18 per 
cent. In a dog’s spleen of average size this is about 5 grams. Since 
about 5 ec. of blood flows from the veins of the spleen every minute,” 
there should. be a variation of the outflow from the vein during this 
time. Roy concludes that the pulsation of the spleen acts as a pump 
by which the circulation through the spleen is aided. Without entering 
upon the discussion of this question it may be noted that this conclusion 
is doubted by Schafer and Moore.” ‘The spleen volume is extremely 
responsive to all fluctuations in the general blood-pressure, and the cireu- 
lation through the organ can be and probably is entirely brought about, 
as in other organs, by the difference between the arterial and venous 
pressure.” Artificial circulation is carried on easier when the organ is 
distended, even after death of all the muscles, and the same seems to 
be the case in the living spleen. W. Miiller has shown that it is impos- 
sible to inject the arteries of the spleen through the veins unless the 
spleen is pretty well distended (p. 85), and this should be the case 
judging by the arrangement of the ampullae. When the pulp is dis- 
tended the reticulum fibrils pull the ampullae open and when it is, 
compressed the ampullae will be closed, making of them a kind of valve. 
30 Jaschkowitz, Virch. Arch., XI. 
31 Mall, Zeit. f. Morphol. u. Anthropol. II, 1900. 
32 Roy, Journal of Physiol., III, 1880-82. 
33‘Mall, 1. ¢., p. 36. 
34 Schafer and Moore, Journal of Physiol., XX, 1896, p. 50. 
