1823.] 



Letters on the Medical School of London, 



same conclusions must, therefore, in 

 reason, be drawn from the examina- 

 tion of the structures \vc meet wilh in 

 living beings, as those which have 

 been deduced from the consideration 

 of the works of Nature in general, by 

 the most intelligent and best informed 

 men. That which we understand 

 seems excellent, in a degree far ex- 

 ceeding our ordinary couceptlons, yet 

 appearing more and more so in pro- 

 portion as it is minutely examined, 

 and attentively considered ; and that 

 we understand so much of the works 

 of Nature, as to warrant us in con- 

 cluding, that we can only cease to 

 admire when we fail to understand. 



The mere art of anatomy, however, 

 abstractedly considered, is exceeding- 

 ly fatiguing and uninteresting: it is 

 tiresome beyond measure, excessively 

 provoking, and at fust perfectly dis- 

 agreeable and disgusting. But it is 

 not, perhaps, possible to consider it 

 altogether abstractedly. He must 

 have a dull heart, indeed, who can 

 behold with unconcern or apathy the 

 multitudinous mass of wonderful and 

 even of beautiful facts, which he en- 

 counters in studying anatomy ; for, if 

 a man possesses tiie smallest portion 

 of line ieoling, he will be astonished 

 »nd delighted at the development of 

 the complete and complicated machine 

 whose structure he is analysing; and 

 he will be powerfully interested by the 

 multiplicity of the organs of the human 

 frame, eaoii performing its peculiar 

 function with the utmost regularity 

 and perfection, and each forming a 

 Contingent part of one beautiful and 

 stupendous construction. It may hap- 

 pen, that he will at first anxiously 

 wonder how life can exist for any 

 length of time, when so many, and 

 such trilling, accidents can derange 

 the movements of this most elaborate 

 machine. Kut his anxiety will subside 

 when he observes how secuiely the 

 most important organs are defended 

 by others of comparatively less iin- 

 purlance ; and when he discovers that, 

 iiowever intricately blended the vari- 

 ous organs may be one with another, 

 there aic always means in reserve to 

 supply the place of any which may 

 have sustained an injury, or even be- 

 come unable to perform their function 

 again. 



Thus the beautiful distribution of 

 the blooil-vessels, wilh their peculiar 

 titness as essential |)arls of the va^t 

 luutUine, will jjowerlully eni^a^e his 



303 



attention: but it is their situation, and 

 their defence from injury, which strikes 

 us as the most interesting circum- 

 stance of all. We tiud that the prin- 

 cipal trunks, carrying an immense and 

 continual column of blood, run in such 

 parts of the body as are least exposed 

 to external injury, deriving support 

 and protection from the bones along" 

 which they pass, or from the large 

 masses of muscle whicli cover them. 

 They pursue their course more or less 

 in a serpentine direction, which dimi- 

 nislies the force of the blood, and pre- 

 vents the vessels froui being strained 

 by the motion of the parts to which 

 they appertain ; and it is particularly 

 observable in those arteries which en- 

 ter very strong and constantly-used 

 nmscles, that they arc protected from 

 compression by a tirni tendinous she;tllj. 

 The two arteries which ascend from 

 the spine towards the head (arteries 

 vertebrales), arc beautifully defended 

 from the inconvenience and danger 

 w hich would ensue upon their being 

 compressed by the bending of the 

 neck: they run through small holes in 

 the bones of the neck, and thus their 

 circulation continues uniini)edcd and 

 uninjured, however frequent, and ia 

 whatever direction, that part of the 

 body be moved. In the back,— whicii 

 is, of all others, perhaps the part most 

 destitute of defence in the whole body, 

 — there is not one important vessel, its 

 large and strong muscles being nou- 

 lished entirely by ve^y small arteries, 

 ramifying in the niost beautiful man- 

 ner and extent. 



Another remarkable provision in the 

 animal economy, is what is terme<l the 

 anastomosis, or inosculation, of arteries ; 

 that is, the minute eomnmnication of 

 one artery with another by means of 

 anastom.itie or inosculating branches, 

 fur the purpose, doubtless, of continu- 

 ing the circulation in case the princi- 

 pal trunk should sustain any injury. 

 If a ligature be tied on the trunk of 

 any of the large arteries, tiie cavity 

 of the vessel nmst necessarily be obli- 

 terated in that parlietil ir part ; but the 

 circulation is contimied by means of 

 the inosculating branches above the 

 ligature, connnunicating with those 

 below it ; and these branches, whicli 

 are naturally very small, become <'on- 

 .sidciably augmented, for the purj)o»c 

 of performing the functions of their 

 new ollice. I (duld giv<! you many 

 other illustrations of this nature; but 

 those which I have mentioned ur<' 



quite 



