COMPARATIVE ANATOMY. 



dated, for the first time in modern days, 

 by that excellent veterinary surgeon Mr. 

 Bracy Clark, in the "Transactions of the 

 Linnaean Society," vol. 3. 



These animals, which are called botts, 

 attach themselves to every part of the 

 stomach, but are in general most nume- 

 rous about the pylorus ; and are some- 

 times, but much less frequently, found in 

 the intestines. They hang most com- 

 monly in clusters, being fixed by the 

 small end to the inner membrane of the 

 stomach, where they adhere by means of 

 two small hooks or tentacula. When re- 

 moved from the stomach, they will at- 

 tach themselves to any loose membrane, 

 and even to the skin of the hand : for this 

 purpose they draw back their hooks al- 

 most entirely within the skin, till the two 

 points of these hooks close to each other; 

 they then present them to the mem- 

 brane, and keeping them parallel till 

 it is pierced through, they expand them 

 in a lateral direction ; and afterwards, 

 by bringing the points downwards, or 

 towards themselves, they include a suffi- 

 cient piece of the membrane with each 

 hook, and thus remain firmly fixed, for 

 any length of time, without any further 

 exertion of the animal. They attain their 

 full growth about the latter end of May, 

 and are coming from the horse from this 

 time to the latter end of June. On drop- 

 ping to the ground, they soon change to 

 the crysalis, and in six or seven weeks the 

 fly appears. This bott is larger and whit- 

 er than that of the oestrus hsemorrhoidalis, 

 which has a reddish cast ; but in its struc- 

 ture, and situation in the animal, resem- 

 bles the former. It is found, however, 

 to hang about the rectum, previously to 

 quitting it,f which the large horse-bott ne- 

 ver do,es. 



Veterinary practitioners do not seem to 

 have decided, hitherto, whether these 

 animals are prejudicial to the horse ; nor 

 even whether they may not be actually 

 beneficial. Their almost universal exist- 

 ence at a certain season, even in ani- 

 mals perfectly healthy, shows that they 

 produce no marked ill effect; yet the 

 holes which they leave, where they were 

 attached to the stomach, could hardly be 

 made without causing some injurious irri- 

 tation. 



For the mode in which these botts gain 

 admission into the stomach, as also for a 

 most interesting general account of their 

 history and structure, see CEstrus, which 

 was furnished by Mr. Clark, and from 

 which the preceding account is borrow- 

 ed. 



The food of carnivorous animals ap 

 preaching in its constituent elements 

 more nearly to those of the animal than 

 that of the herbivorous tribes, is more 

 easily reduced into the state which is re- 

 quired for the nourishment of the body 

 in the former than in the latter case. 

 Hence arises a leading distinction be- 

 tween the stomachs of these classes. In 

 the latter animals, the oesophagus opens 

 considerably to the right of the great ex- 

 tremity, so as to leave a large cul de sac 

 on the left side of the stomach; and the 

 small intestine commences near the car- 

 dia, leaving a similar blind bag on the 

 right. The food must be detained for a 

 long time in such a stomach, as the pass- 

 age from the oesophagus to the pylorus 

 is indirect, and highly unfavourable to 

 speedy transmission. Animals of the 

 mouse kind, and the rodentia, show this 

 structure very well ; it is very remark- 

 able in the mus quercinus, (Cuvier, " Le- 

 ons," &c-. torn. 5. pi. 36. fig. 11.) In 

 the carnivora, the stomach, which is of a 

 cylindrical form, has no cul de sacs ; the 

 oesophagus opens at its anterior extremi- 

 ty, and the intestine commences from the 

 posterior ; so that every thing favours a 

 quick passage of the" food. Animals 

 of the weasel kind, which are very truly 

 carnivorous, exhibit this structure the 

 most completely. The seal also exem- 

 plifies it, and the lion. (Cuvier, pi. 36. 

 fig. 7.) 



The most complicated and artificial ar- 

 rangement, both with respect to struc- 

 ture and mechanism, is found in the 

 well-known four stomachs of the rumi- 

 nating animals with divided hoofs: of 

 this we shall take, as examples, the cow 

 and sheep. 



The first stomach or paunch, (rumen, 

 penula, m;ignus ventor, ingluvies, is by 

 far the largest in the adult animal ; not 

 so however in the recently born calf or 

 lamb. It is divided externally into two 

 saccular appendices at its extremity, 

 and it is slightly separated into four 

 parts on the inside. Its internal coat 

 is beset with innumerable flattened pa- 

 pill*. 



This is followed by the second sto- 

 mach, honeycomb bag, bonnet, or king's 

 hood, (reticulum, ollula,) which may be 

 regarded as a globular appendage of 

 the paunch ; but it is distinguished from 

 the latter part by the elegant arrange- 

 ment of its internal coat, which forms 

 polygonal and acute-angled cells, or su- 

 perficial cavities. 



The third stomach, which is the small- 

 est, is called the manyplus, which is a 



