Tubercles, and all their concomitants as above detailed, are also met with in the liver, though not so frequently as in the lungs. They constantly occur in the _clyars_ (mesenteric or lacteal glands) which on this account are much above their usual size, and are occasionally found in other parts; but I need not proceed in their description, as sufficient has been said about them to enable the unprofessional reader to understand their relation to the complaints. Fluke worms and hydatids are almost constant attendants on rot, and seemingly most important ones, especially the former, which have, I may say, kept a great bulk of the learned and unlearned for many years in a perpetual bustle, and have so effectually hoodwinked writers on this subject, as to prevent them seeing the truly important points in the disease. For this reason, I hold them worthy of particular description; as it is only by becoming acquainted with their history and habits that we can form correct ideas either of their mode of origin or of their supposed ability to cause rot. (162.) _The Liver Fluke_ (_fasciola hepatica_ or _distoma hepaticum_, _Fig. 6._ _Plate_ I.) derives its name from the resemblance it bears to the plaice or flounder, though its shape has been more aptly compared to that of a melon seed. It is flat and oval, of a brownish-yellow colour, and varies in size from that of a pin-head to one inch in length, and half an inch in breadth. Each worm is bisexual or hermaphrodite, on which account they multiply with great rapidity. The generic name--_distoma_--signifies having two pores, _a.b. Fig. 6, Plate_ I., and is for this reason applied to it. The nipple-like body at the extremity _a._ contains the orifice of the pore or opening leading to the female division of the generative apparatus, situated between _a._ and _b._ In this cavity are formed the eggs, which are at intervals protruded, to be hatched when floating in the sheep's bile. The male organ is situated in front of the ventral pore. The anterior opening _b._ is equivalent to a mouth, and leads inwards and backwards, communicating with the intestinal canals _c._, which are easily made out in the recent animal, from their containing dark bile, and which, as in other creatures low in the scale of being, serve the double purpose of a digestive and circulatory apparatus; that is to say, the stomach first prepares a fluid which is equivalent to blood, and then distributes it throughout the body.[33] [33] The examination of fluke worms is much facilitated by placing several of various sizes flat upon a slip of glass, and allowing them to dry in this position. On holding the glass between a bright light and a lens, and looking through the latter, the distribution of the vessels, and the position and form of the eggs, are beautifully displayed.