Bancrofti is known to live in the lymphatic glands, and its embryos Microfilaria sanguinis hominis nocturna, passing by the thoracic duct, reach the blood-vessels and circulate in the blood.
In other cases very serious disorders of the lymphatic system are brought about, of which the most marked is perhaps Elephantiasis.
This state of affairs has no antecedent improbability about it, since in the Vertebrata the coelom is unquestionably confluent with the haemal system through the lymphatic vessels.
A characteristic feature of cancer is the carrying of the epithelial cells (which are the essential element of the growth) to the nearest lymphatic glands, and in cancer of the stomach the secondary implication of the glands may cause the formation of large masses between the stomach and the liver, which may press upon the large veins and give rise to dropsy.
The invasion of the lymphatic glands and the spreading of the growth into neighbouring organs, render the successful operative treatment of gastric cancer hazardous and disappointing.