on tJie Porosity of Bodies. 289 



indifiference. This much is certain, modern physiology so far 

 adopts a porosity of the organic membranes, as to admit that 

 these are permeable for liquids and gases, but not to allow the 

 passage through them of any solid substance. Thus, with re- 

 ference to the latter, the following enunciation has been given 

 by Johannes Miiller : — '^ The appearance of globules in secre- 

 tions, presupposes formation of the same at the moment of 

 separation. They cannot pass out of the blood through the 

 capillaries*.^' Further, it is said by Henle in his treatise on 

 ' Eiterinfection,' " I regard the vascular wall as a hermetically 

 closed membrane, which keeps at a distance from the blood 

 the exciters to putrefaction — microscopic organisms t.^' 



The full validity of these enunciations has, however, recently 

 been called in question, through various physiological and patho- 

 logical facts, which deserve the greatest attention, although no 

 one has hitherto been able to find for them sufficient explanation. 

 To these belongs, in the first place, the penetration of the fat 

 globules into the lacteals and blood-vessels, concerning which it 

 has with tolerable certainty been shown, that they as such get 

 through the intestinal walls without previous chemical change J. 

 Further, may be mentioned what experience shows to take 

 place, the penetration, in the form of minute globules, of the 

 mercury contained in blue ointment through the skin into the 

 humours, whereof salivation and other symptoms aff^ord proof to 

 every physician. The powerfully healing effects of the rubbing 

 in of lard and other fatty ointments, do not well admit of being 

 otherwise explained. Now, after the passage of metallic mer- 

 cury into the blood of animals — partly rubbed into uninjured 

 parts of the skin, and partly given them in food — had been 

 microscopically shown, which was first done by Osterlen§, who 

 arrived at the same result in his experiments with carbon, 

 these observations were most fully confirmed by Eberhardt||, 

 Mensonides^, and Donders**, and extended to the penetration 

 of particles of sulphur and starch-granules. So that consequently 

 the possibility of the penetration of finely-divided substances 



* Handbuch der Physiologie des Menschen, 4th edit., vol. i. p. 202. 



t Handbuch der rationellen Pathologie, vol. i. 1847, p. 7(^7- 



X F. Bidder and C. Schmidt, Die Verdauungss'dfte und der Stoffwechsel, 

 1852, p. 250. 



§ Archiv fur physiol. Heilkunde, 1843, p. 536 j and Zeitschrift fur 

 rationelle Medizin, vol. v. p. 434. 



II Henle's and Pfeufer's Zeitschrift fur rat. Medizin, New Series, vol. i. 

 1851, p. 406. 



% Aldus Mensonides, De absorptione molecularum solidarum nonnuUa. 

 Traj. 1848. 



** Nederlandsch Lancet, vol. iv. ; and Zeitschrift fur rat. Medizin, 1851, 

 p. 415. 



PhiL Mag. S. 4. Vol. 8. No. 52. Oct. 1854. U 



