STRONGYLUS ARMATUS. 
369 
)r ischaemia of that portion of the intestine to which the artery 
s distributed, and consequently paralysis of one or more of 
he sections of the digestive tube, the secretions and move- 
nentsof which are suspended. Cohn and Panum have shown 
experimentally, in fact, that such are the results of embolism 
|)f the great mesenteric artery. The ischaemic portion of the 
ntestine becomes at first pale, then of a dark-red color ; the 
nucous membrane is swollen, there are hemorrhagic infarcts, 
erous exudates, ecchymoses, and sometimes a considerable 
ncrease of the organ in volume. * 
These phenomena, which are almost immediately consecu- 
ive, are related to the total absence of pressure in the capil- 
aries of the artery, and even in the venous trunk succeeding 
hem, as far as the next veinule, where the circulation can go 
•n freely. The blood flows from this point towards the cap- 
tlaries, where the tension is nearly nil, and soon causes en- 
orgement, and even small hemorrhages. In consequence of 
11 this disturbance, there are colics, which rapidly disappear 
: the obstructed artery is of small calibre; for the collaterals 
oon supplement it. The duration of these colics depends 
pon the facility with which this collateral circulation can be 
fleeted. It is sometimes easier in a large branch nearer the 
runk of emergence, and this explains why an attack of colic 
bat appears very serious will quickly disappear. 
Otherwise, the establishment of the collateral circulation 
7 
lays an important part in the post-ischaemic hyperaemia; and 
lis collateral or compensatory hypergemia is related to the 
lerease of blood pressure in the vessels adjoining the obliter- 
ted one, as Feltz has shown. When it does not produce ir- 
sparable lesions the equilibrium is quickly restored, and all 
rouble disappears. 
r"The circulation disturbances of the intestine cause a local 
'p7 
aralysis in it, stagnation and consequent fermentation of its 
ontents, with an abundant production of gas. The enteralgia 
iduced in the healthy portions causes energetic contractions, 
hich frequently lead to volvulus and invaginations. Fried- 
erger and Frohner have often observed the rotation on its 
xis of the left part of the large colon—that is, its free portion, 
