•74 Dr. Barry's Account of the Discoveries of Keber 



Now this circumstance, that, in thus proceeding, porosity is 

 perceptible in entirely fresh organic formations too, immediately 

 meets the objection which perhaps might be taken — that this 

 porosity is merely an artificial product, the effect of drying. I 

 would here however bring to especial remembrance the fact, 

 that, as experience shows, organic formations by no means lose 

 their natural texture through mere drjdng; for dried animal and 

 vegetable textures, through fresh moistening, reassume their 

 former appearance and original condition *. 



Very conspicuous are the pores in the roots of plants when 

 examined after proceeding in the following manner. Take fresh 

 roots filled with their juices or after having lain in water, — 

 remove the earth, — apply gentle scraping, and then spread out 

 upon glass for examination, without a covering of glass, the de- 

 tritus adhering to the knife. Then, as the fine scrapings on the 

 glass dry up and the moisture contained in their interstices 

 evaporates under the eyes of the observer, the pores in their 

 substance, with intense illumination, are brought out in so 

 distinct a manner that the whole scrapings appear composed of 

 a network of variously twisted and overlapping filaments and 

 scales, leaflets and granules ; and in fact everywhere present a 

 composition like that of sponge. The addition of water having 

 been avoided, there is besides observable in the neighbourhood 

 of the scrapings some detritus still much finer than the rest, in 

 which one may very well recognize the disposition of the granular 

 materials to form minute filaments, and the interstices thereby 

 arising between them. It requires however a good light and a 

 trustworthy microscope to recognize these pores of the roots of 

 plants ; yet a linear enlargement of from 200 to 300 is always 

 sufficient, and from the greater clearness thereby eflfected, is 

 preferable to higher magnifying powers. 



Having now, according to the above-mentioned methods, ex- 

 amined with perseverance and care all the animal and vegetable 

 formations of many classes in both kingdoms which it was pos- 

 sible to get access to, as well as all sorts of inorganic bodies, I 

 consider myself entitled to make the enunciation, that now-a- 

 days porosity in all solid bodies admits of optical demonstration. 

 Far, however, am I from maintaining that every light-reddish 

 glimmering place in fine scrapings is always an open space; 

 rather do I unconditionally admit that many of them are covered 

 by other delicate lamellae. Yet in my opinion this circumstance 

 proves nothing against the porosity of bodies generally, which 

 is more required to be established than the perception and 

 measurement of individual pores : though during an occupation 



* J, Liebig, U c. p. 2. 



