ECHINOCOCCUS HOMINIS

This creature, which is the larva of the Tinæa Echinococcus , is a very common parasite infesting man, and has been found in the human lungs, heart, kidneys, liver, spleen, ovaries, breasts, membrane of the throat, and the bones. The disease to which it gives rise is of a very long and painful nature, frequently terminating fatally, and one in which no remedies have hitherto been found of any avail. The part of the human economy most frequently attacked by the ravages of the Echinococcus is the liver, in the substance of which it gives rise to the formation of a hydatid tumour. This tumour is composed of a thick-walled cyst or bag, within which is another of a much more delicate texture. “This latter membrane is the mother-sac of the Echinococcus embryo” (Huxley), and corresponds with the germinal membrane of Profe or Goodsir. It is studded with innumerable transparent cells, varying as extremes of measurement from 1 ⁄ 10000 th to 1 ⁄ 3000 th of an inch. It is the seat of development of innumerable Echinococci, and to this membrane, in a fresh hydatid tumour, they are found connected by a delicate membrane, either singly, or more commonly in clusters, the number of individuals on the cluster varying from 10 to 100 or more, as shown in the annexed woodcut.” [271] [271] Aitken. IMG:596405606043057898_i619-1.png: The size of the embryo varies from 1 ⁄ 18 th to 1 ⁄ 20 th of a line to 1 ⁄ 10 th to 1 ⁄ 18 th, according as it is elongated or contracted. Fig. 2 represents two Echinococci. In the one the head is drawn within the vehicle, and in the other it is extruded. IMG:596405606043057898_i619-2.png: Fig. 2. IMG:596405606043057898_i619-3.png: Fig. 3. Fig. 3 represents a transverse view of an echinococcus; S S are suctorial discs; the hooklets may be seen encircling a membranous disk. IMG:596405606043057898_i619-4.png: Fig. 4. In Fig. 4 we have a representation of the circlet of these hooklets, B , which are thirty-four in number; C gives various views of separate hooklets; b is the base; c the central extremity; e the hooklets viewed upon their concave or inferior border. The dotted lines connecting f , g , k , represent the outer surface of the neck, and runs through the fixed point of the three hooks which move upon the central fixed proce , as on the pivot. The inhabitants of Iceland are said to suffer severely from the effects of the Echinococcus Human us; it has been computed that a sixth of the population of the island are attacked by it.