198 Notes, iii. 4, . *. 



respectively. Any one who reads A.'s description will see that this view of the matter 

 is utterly untenable, and would turn every sentence in the description into nonsense. 

 There can, I think, be no possible doubt that the three cavities are the right ventricle, 

 the left ventricle, and the left auricle. Why it may be asked did A. omit the right 

 auricle ? Simply because he looked on it as a venous sinus, being'a part_ not of the heart but 

 of the great vein (/.^. superior and inferior venae cavse). That he so regarded it, is plain 

 from his always speaking pf the superior and inferior venae cavae as forming a single 

 vessel, not as two distinct ones, and he even says in one place {H. A. iii. 3, 8) that the heart 

 appears very much like a part of the great vein, being interposed between*its upper and • 

 lower divisions. Galen held a precisely similar view of the right auricle. " Galien,"'says 

 Daremberg (i. 387), "considere la veine cave syperieure comme une continuation directe 

 de la veine cave inferieure, I'oreillette droite h'etant qu'un diverticulum ou un . lieu de 

 passage." Such a vi.ew was quite natural ; for the right auricle " semble formee par fa 

 reunion des veines caves qui s'ouvrent aux deux extrenlites superieure et inferieure de 

 cette oreillette" (CMZz/^r, Z^pjwj, iv. 199). This being understood, A.'s description of 

 the heart becomes fairly intelligible. Here are the main parts of it, as I interpret 

 them. " The heart has three cavities. The largest is placed on the right (right ventricle); 

 the smallest on the left {left auricle) ; and the one of middle size {left -Ventricle) lies in the 

 middle. All these cavities — even the two smaller ones — have openings in them which 

 lead to the lung {pulmonary artery; pulmonary veins ; and, for the left vlntricle, the fcetal 

 ductus arteriosus), but it is'only in one of them {right ventricle) that the communication 

 with the lung is conspicuous {pulmonary artery). The largest cavity {right ventricle) is 

 connected with the great blood-vessel {right auricle which is simply dilated junction of 

 ■ vetue cava) ; and thq middle cavity {left ventricle) is connected with the aorta. Moreover 

 passages {pulmonary artery and veins) lead from the heart to the lungs, and divide after 

 the same pattern as the windpipe, their branches accompanying the branches of this latter 

 throughout the whole lung, and the former being placed above the latter,-- There is no 

 communicating passage between these two systems of branches, but those which come from 

 the heart receive the breath from the others, in consequence of their close contact with 

 them, and transmit it to the heart. For one of the passages {pulmonary artery) leads to the 

 right cavity {right ventricle) and the other {pulmonary veins) to the left cavity {left auricle) " 

 {H. A. i. 17). And again, "The heart in the largest animals has three cavities. The 

 largest of these {right ventricle) is on the right, and is above the rest ; the smallest 

 {left auricle) is on the left ; and the middle one in size {left ventricle) is also the middle 

 one in position. Each of the two latter cavities is much smaller than the largest one 

 {right ventricle). All three have openings which lead to the lungs ; but these openings 

 are so small as to be scarcely visible, excepting in- one ciyity {right ventricle). . Thq, great 

 blopd-vessel {right auricle and 'venm cavce) is connected With the largest cavity {right 

 yentricle), and after passing through the centre of the cavity issues from it again in the 

 form of a blood-vessel {pulmonary artery), as though the cavity were a part of the vessel, in 

 which the blood collected as in a reservoir. The aorta issues from the middle cavity {left 

 ventricle), having however a much narrower tube [than the pulmonary artery]. * The 

 great vessel {veme cavce'plus right auricle) passes through the heart, and after issuing from 

 it {cu pulmonary arlery) extends into the aorta {by the ductus arteriosus). [Th^ great vessel 

 is membranous and skin-like ; but the aorta, which is smaller than the great vessel, is very 

 tendinous, and, as it extends upwards tovvards the head and downwards towards the 

 lower parts, gets narrower, and assumes altogether the character of sinew (cf. Npte 20). 

 The great vessel sends first a branch upwards above the heart, to the lung and the 

 junction with the aorta {pulvionqry artery and ductus arteriosus), this branch forming a 



