271 



taining only the briefest bint of matters wbicb, tbongb not necessarily 

 in tbeir ultimate scientific miniitia?, must be clearly comprebended in 

 order to acquire a symmetrical and satisfactory view of tbe tbemo as a 

 practical collation of facts to be remembered, analyzed, applied, and 

 utilized. 



It was tbe great Bacon wbo wrote: "Tbe buman body may be com- 

 l)ared, from its complex and delicate organization, to a musical instru- 

 ment of tbe most perfect construction, but exceedingly liable to de- 

 rangement." In its degree tbe remark is equally applicable to tbe equine 

 body, and if we would keep it in tune and i^rofit by its barmouious 

 action we must at least acquaint ourselves witb tbe relations of its parts 

 and tbe mode of tbeir co-operation. 



ANATOMY. 



Tbe bones, tben, are tbe bard organs wbicb in tbeir connection and 

 totalit}' constitute tbe skeleton of an animal. Tbey are of various 

 forms, of wbicb tbree — tbe long, tbe flat, and tbe small — are recognized 

 in tbe extremities. Tbese are more or less regular in tbeir form, but 

 present upon tbeir surfaces a variety of aspects, exbibitiug in turn, 

 according to tbe requirement of eacb case, a rougbened or smootb sur- 

 face, variously marked witb grooves, crests, eminences and depressions, 

 for tbe necessary muscular attacbments, and, as before mentioned, are 

 connected by articulations and joints, of wbicb some are immovable and 

 otbers of a movable kind. 



Tbe substance of tbe bones is composed of a mass of combined eartby 

 aud animal matter, surrounded by a fine, fibrous enveloping membrane 

 (tbe i^eriosteum) wbicb is intimately adberent to tbe external surface of 

 tbe bone, and is, in fact, tbe secreting membrane of tbe bony structure. 

 Tbe bony tissue i)roper is of two consistences, tbe external portion be- 

 ing bard and "compact," and called by tbe latter term, wbile tbe inter- 

 nal, known as tbe " spongy tissue" or " areolar," is also of a consistency 

 corresponding witb tbese descriptive terms. Tboseof tbe bones wbicb 

 possess tbis latter consistency contain also, in tbeir spongy portion, tbe 

 medullary substance kuown as marroic, wbicb is deposited in large 

 quantities in tbe interior of tbe long bones, and especially wbere a cen- 

 tral cavity exists, called, for tbat reason, tbe medullary cavity. Tbe 

 nourisbment of tbe bones is effected by means of wbat is known as tbe 

 nutrient foramen, wbicb is an opening establisbed for tbe passage of 

 tbe blood vessels wbicb convey tbe necessary nourisbment to tbe interior 

 of tbe organ. Tbere are otber minutia) concerning tbe nourisbment of 

 tbe skeleton, sucb as tbe venous arrangement and tbe classification of 

 tbeir arterial vessels into several orders, wbicb, tbougb of interest as 

 an abstract study, are not of sufiBcient practical value to refer to bere. 



Tbe active organs of locomotion, tbe muscles, form, speaking gener- 

 ally, tbe flesby covering of tbe external part of tbe skeleton aud sur- 



