Colic in Solipeds froju VefviiiiOKs Embolism . 215 



Embolisms. These come ver}- naturally from the formation 

 of thrombi in the various arteries. The coagulum determined 

 by the presence of the worms, tends to undergo retrogressive 

 changes notably fatty degeneration, to which germs brought on 

 the worms or in their alimentary canals contribute. This to- 

 gether with the movements of the parasites tends to break up 

 the mass, and minute portions are washed on into the differ- 

 ent smaller vessels. Soon these reach divisions which are too 

 small to admit them, which are accordingh' occluded and the cir- 

 culation through them abolished. The presence of microbes as 

 well as fibrine contributes to cau.se further coagulation, more ab- 

 solute emboli.sm and arrest of the circulation. 



It is further alleged that the .sexual instinct in the summer 

 months (May to August) leads the worms to leave the aneurisms, 

 to pass through the smaller divisions to the caecum or colon where 

 alone full sexual evolution is possible. In these migrations the)' 

 cause the thrombosis of the smaller trunks and determine the 

 verminous congestions of the bowels which are especially com- 

 mon in these months. 



Disturbances of the Intestinal Circulation. As these 

 usually occur in the lines of distribution of the anterior 

 mesenteric arter}' a knowledge of its divisions and their destina- 

 tion and anastomoses, is essential to an intelligent understanding 

 of the pathogenesis and lesions. As first pointed out b}'^ Lecoq 

 the anterior mesenteric artery is divided into three primary bun- 

 dles : (a) ^ left ot 15 to 20 trunks which are destined to the 

 small intestine ; (b) a right which gives oflf csecal branches, one 

 to the double colon, and one to the ilium to anastomo.se with the 

 last trunk of the left bundle ; and (c) an ajiterior which gives 

 one branch to the .second division of the double colon and anasto- 

 moses with the colic branch of the right bundle at the pelvic 

 flexure ; and a second branch to the floating colon to anastomo.se 

 with the posterior mesenteric artery. 



The divisions of the left bundle anastomose so freely with each 

 other in the mesentery and immediatelj' above the intestine that 

 the blocking of any one branch cannot entirely arrest the ciicu- 

 lation in the corresponding part of the intestine. It may how- 

 ever produce a partial local stagnation in the vessels of a short 

 loop of intestine, resulting in oedematous infiltration and thicken- 



