PRODUCTS, ADVENTITIOUS. 



87 



times be seen in the urine coated with saline 

 matters ; but this is merely a rudely analogous 

 condition to those previously mentioned. 



(b.) Postal (petrifactions). At the opposite 

 extreme to cases in which a simple elementary 

 cell becomes the depositary of calcareous mat- 

 ter, stand those remarkable instances in which 

 an entire individual becomes more or less com- 

 pletely invested with a coating of such matter ; 

 while subsequent desiccation of the tissues 

 (with, very rarely, partial calcification of these) 

 mummifies the entire frame. 



(c.) Placental. Calcareous concretions are 

 of not uncommon occurrence in the human 

 placenta. Hannover found them in large 

 number in twenty of two hundred placentae. 

 They are of white colour, rounded or branched 

 in shape, and composed of phosphate of lime ; 

 generally seated on the uterine, rarely on the 

 foetal, surface, near the border. The age and 

 constitution of the mother or of the child, 

 separation of the placenta, and haemorrhages, 

 appear to Hannover to be without influence on 

 their production. 



(d.) Vascular. Arteries, (1.) Parietal 

 There are few conditions more familiar to the 

 observer than the calcareous deposition in the 

 coats of arteries, long erroneously styled 

 " ossification " of these tubes. The saline 

 materials, giving the ossiform aspect to the de- 

 position, assume four different forms: 1. That 

 of a gritty looking substance sprinkled over 

 the internal surface of the vessel; 2. That of 

 patches of variable size and thickness, some- 

 times sufficiently extensive to convert a con- 

 siderable tract of the vessel into an inflexible 

 tube ; 3. that of small rounded or shapeless 

 masses, protruding or not into the interior of 

 the vessel ; 4. that of prominent spiculae ; 

 when their anatomical constitution appears 

 more allied than under other circumstances to 

 that of bone. 



Mr. Brande found these incrustations to 

 consist of sixty-five and a half per cent, of 

 phosphate of lime and the rest of animal 

 matter. These proportions must of course 

 vary in different cases : thus Scherer * found 

 " ossified " arterial membrane composed of 



Organic matter 7.292 



Phosphate of lime 63.636 



of magnesia.. 10.909 



Carbonate of lime 18.181 



M. Bizot -j~ has given a tabular view of the 

 relative frequency with which different parts 

 of the aorta become the seat of this condition ; 

 and from this we learn with more precision 

 than could be otherwise attained, that the 

 points at which the different branches are 

 given off are far the most frequently im- 

 plicated ; and that the posterior surface of the 

 thoracic and abdominal divisions of the vessel 

 suffers more frequently than the anterior in the 

 proportion of 11 to 1. 



The precise seat of calcareous deposit, in 

 respect of the coats of the tubes, has been 



* Simon, loc. cit. p. 477. 



t Mem. de la Societe He'd. d'Observation, t. i. 



made matter of much disputation. We have 

 ourselves found that in the aorta the new 

 matter is thrown out between the middle and 

 internal coats, and in the vessels of the limbs 

 either in this situation or in the actual sub- 

 stance of the middle coat ; or, to use the 

 language which the modern anatomy of arte- 

 ries would require us to adopt, we should say 

 that the saline matter is deposited in the aorta 

 in the striated and longitudinal-fibrous tunics 

 between the epithelial and circular-fibrous 

 tunics ; and also, in the arteries of the limbs, 

 in the substance of the circular-fibrous and 

 true elastic coats. 



There are three kinds of deposit, of com- 

 mon occurrence in the arteries, set down by 

 writers as the nidus in which saline accumu- 

 lation may occur: these are the " atheromatous 

 matter," the " white spot," and the " cartila- 

 ginous patch." The origin and nature of these 

 matters require to be briefly examined. 



The atheroma of the arteries and cardiac 

 valves is a yellowish matter occurring in 

 minute' particles, hardly larger than grains 

 of sand ; separate or clustered into small 

 patches ; most abundant at the points where 

 vessels are given off from the affected trunk ; 

 obviously seated underneath a coating of epi- 

 thelium, and even probably under the striated 

 tunic of the artery, (as when an attempt is 

 made to peel it away by raising these two 

 coats, it is in part removed with them, and 

 remains partially adherent to the deeper- 

 seated tunics) ; and distinctly unctuous to the 

 feel, when accumulated in any quantity. The 

 substance is indeed of fatty nature. Gluge * 

 found that " an enormous deposition of fat 

 globules solely and alone constitutes this mor- 

 bid state, and in fact even with the naked eye 

 a remarkable similarity may be perceived be- 

 tween the atheromatous state and certain 

 forms of fatty deposition in the liver." Mr. 

 Gulliver f has independently ascertained the 

 same fact, and illustrated his description by 

 figures.;}: 



The researches of M. Bizot have very clearly 

 established that this atheromatous matter be- 

 comes, with the progress of things, the seat of 

 one or other of two series of changes, termi- 

 nating in the one instance in ulcerous soften- 

 ing, in the other in calcareous deposition. The 

 stages of the ulcerous softening are four : in 

 the first the yellow matter becomes slightly 

 prominent on the surface of the vessel, and 

 the superficial fibres of the " middle " tunic 

 lose their natural consistence ; in the second 

 the internal membrane is raised into little emi- 

 nences by the accumulation of a matter which 

 is sometimes liquid and puriform-looking, 

 sometimes floury and dry, and occasionally 

 containing minute shining scales, some of 



* Anat. Micros. Untersuchungen, Erstes Heft, 

 S. 130, 1838. 



f Med. Chir. Transactions, vol. xxvi. p. 86, 1843. 



j We have occasionally found plates of cbolesterin 

 in greater abundance than oil-globules, a fact 

 having an obvious connection with the established 

 circumstance of the excess of cholesterin in the 

 blood of old persons. 



G 4 



