In Hemiptera only eleven and in Collembola only yolk, and that the mesenteric epithelium becomes reinforced by six abdominal segments have been detected.
In this way secondary abscesses, secondary tubercle glanders and nodules, &c., result; in typhoid fever there is secondary invasion of the mesenteric glands, and clumps of bacilli are also found in internal organs, especially the spleen, though there may be little tissue change around them.
In some corals, in which all the septa are entocoelic, each new system is embraced by a mesenteric couple; in others,in which the septa are both entocoelic and exocoelic, three septa are formed in Il FIG.
At post-mortem get enlarged lymph nodes (mesenteric and abdominal) and focal necrosis of the liver and spleen.
Cells pass to the mesenteric lymph nodes where the immune response is amplified.