PRODUCTS, ADVENTITIOUS. 



113 



varying degrees of dilution of the acid. That 

 the involucrum fades simply, without being, 

 as was at one time supposed, destroyed, is 

 commonly obvious on simple inspection ; it 

 appears as a sort of thin, transparent halo 

 round the nuclei. But, were there any doubt, 

 this would be removed by the addition of 

 solution of iodine *, which restores the clear 

 definition of the cell-wall. The fading of the 

 involucrum is, however, an early stage of so- 

 lution ; for, if much acid be added, the halo 

 disappears and cannot be restored. In re- 

 spect of this disclosure of the nucleus three 

 opinions have found their supporters : (a.) 

 that a simple or compound nucleus, pre-exist- 

 ing in either form, is simply rendered visible 

 by the acid ; (b.) that it is exposed and, be- 

 sides, split up into parts; (<?.) that it is an ap- 

 pearance altogether produced by the acid. 

 That the first of these opinions is the correct 

 one, appears (if on no other grounds) from 

 what has been said in a previous page on the 

 discovery of the nucleus in recent unchanged 

 pus. 



Mineral acids, if dilute, do not dissolve the 

 corpuscles ; if concentrated, dissolve them 

 completely. '.Caustic alkalies form a jelly with 

 them ; their carbonates, as also muriate of am- 

 monia, change them similarly but more slowly. 

 The action of the latter on pus was observed 

 by J. Hunter on a large scale, and ascribed 

 by him to coagulation of the liquor puris. Dr. 

 J. Davy showed, by allowing the corpuscles to 

 settle, decanting the supernatant fluid, pour- 

 ing some of the muriate upon this, and observ- 

 ing that no viscidity followed, until corpuscles 

 had been added, that the change depended 

 upon these. Dr. Wood f ascertained that the 

 muriate causes the corpuscles to adhere with 

 some closeness to each other. 



Pus-corpuscles contain a very little phos- 

 phate of lime, and consist essentially of a pro- 

 tein-compound. Their constituent substance 

 has been given the special title purhtm by 

 Koch, purulina by Michelotti ; a mode of 

 naming it which must be abandoned if, as 

 Lehmann and Messerschmitt maintain, the nu- 

 cleus and involucrum belong to two different 

 varieties of protein, the former being com- 

 posed of venous, the latter of arterial, fibrin. J 

 But this view is, it is scarcely necessary to 

 add, itself far from being established, as also 

 that of persons who (imitating Ascherson) 

 hold the centre of the nucleus to be composed 

 of fat, and its peripheral part of albumen. 



Pus differs chemically from blood in the 

 states of health and of hyperinosls in the 

 proportion of its ingredients, much more than 

 in their nature as might readily be imagined. 

 But quantitative analyses are as yet so imper- 



* The corpuscles, and especially the nuclei, attract 

 the iodine from the fluid in which they swim ; for, 

 while they darken, this fluid loses its yellow-brown 

 colour. 



f De puris natura atque formatione. (Berol.) 

 j Medicin. Vierteljarhsch rift von Koser and Wun- 

 derlich, 1842, S. 247. The same writers regard the 

 molecular granules of pus as composed of yet ano- 

 ther variety of protein-compound, resembling Ke- 

 ratin. 



VOL. IV. 



feet, that very different general inferences may 

 be deduced from them according to the selec- 

 tion made of published analysts; it is true 

 this may also in part depend on the actual vari- 

 ation in the proportions in different specimens 

 of pus. Thus we may prove by one set of 

 experiments that pus contains more water than 

 healthy, and a fortiori than hyperinotic, blood ; 

 and, by another, that pus is on the contrary a 

 more concentrated fluid than either. And 

 whichever be the opinion adopted, theoretical 

 explanation and support may readily be found 

 for it. The following general inferences are 

 likewise, we confess, to be accepted with 

 caution. 



Pus contains more albumino-fibrous sub- 

 stance than the liquor sanguinis of either spe- 

 cies of blood, less than the blood in mass, com- 

 prising the red corpuscles. The latter point 

 obviously depends on the fact that the cor- 

 puscles are, as such (unless accidentally and 

 in very minute proportion), retained within 

 the vessels ; whereas pus is formed outside 

 them. But how comes it that pus contains 

 proportionally more albumino-fibrous material 

 than the liquid part of the blood that part 

 of the blood which is exuded in inflamma- 

 tion, and which forms the substance for the 

 evolution of the purulent matter ? The pecu- 

 liarity (as suggested by Lebert) is probably 

 due to partial solution of the red-corpuscles 

 in the liquor sanguinis, and transudation ot 

 that dissolved substance ; an explanation not, 

 we may observe, without apparent connection 

 with the established fact of the decrease of red 

 corpuscles in hyperinotic blood. To this source 

 (as well as to extravasation) ma}', perhaps, be 

 referred the occasional appearance of a little 

 iron among the elements of pus. 



Fat is much more abundant in pus than in 

 blood ; the high ratio of cholesterin in the 

 former (as ascertained by Valentin *, Von Bibra 

 and Wright) comes in confirmation of the fact 

 established by Becquerel andRodier-j-, that the 

 ratio of cholesterin in the blood is always in- 

 creased in inflammation. The saline consti- 

 tuents of the two fluids do not differ very 

 materially. 



Pus possesses a remarkable power of re- 

 sisting decomposition ; at the end of months 

 some corpuscles may still be found unchanged, 

 among others that are dissolved. It even re- 

 tards the putrefaction of substances with 

 which it is brought in contact, as shown by 

 the experiments of J. Hunter and Everard 

 Home. The latter observed that pieces of flesh 

 placed in fresh pus underwent gradual dimi- 

 nution of weight, and eventually solution, 

 without any evidence of putrefaction being 

 manifested. Ultimately, pus does putrefy 

 however ; the occurrence of the change being 

 much hastened by the presence of blood, 

 mucus, or other organic fluids. Acidity, as 

 already hinted, is one of the earliest signs of 

 the change. 



* In one of Valentin's Analyses (Repertorium 

 S. 307, 1838) the proportion of cholesterin is so high 

 as 11.86 per 1000. 



t Gazette Mc'dicale de Paris, 1844. 



