152 DR. KEBER, ON THE POROSITY OF BODIES. 



are numerous openings instead.) The shell 



usually thick, perhaps always perforated by 



fine pore-canals. 



Gen. Glandulina, Nodosaria, Orthocerina, Dentalina, Frondi- 



cularia, Lingulina, llimulina, Vaginulina, Webbiua, 



Conulina. 



3. Group SOKOIDEA. 



Chambers grouped in irregular masses. 



10. Fam. AcERVULiNiDA. — Chambers usually globose, disposed very irre- 

 gularly one upon another, and of pretty 

 imiform dimensions ; shell finely perforate, 

 and with a few larger openings at indeter- 

 minate places. 

 Gen. Acervuliua. 



MiKROSKOPISCHE UnTERSUCHUNGEN UEBER DIE POROSITAT DER KoRPER. 



Nebst &c. F. Keber. (Microscopical Eesearches on the Porosity of 

 Bodies. Together with a Memoir on the entrance of the Spermatic 

 Cells into the Ovum. By F. Keber.) 



We shall, on the present occasion, confine our remarks to the 

 former of the subjects treated on by Dr. Keber, an abstract 

 of whose Memoir on the Porosity of Bodies, furnished by the 

 Author and translated by Dr. Barry, appears in the ' Philoso- 

 phical Magazine' for October and November, 1854. Dr. 

 Barry has also appended to it what he terms ' Confirmations ' 

 of Dr, Keber's views. 



Dr. Keber states, that after many fruitless attempts, he has 

 been so fortunate as to discover in the substance of all 

 organic bodies already formed (though what that means is 

 not very obvious), microscopic spaces from 1-1 2000th to 

 l-48000th of an inch in diameter ; and generally, in all bodies 

 which he has examined, to recognize signs of an optically de- 

 monstrable and measurable microscopic porosity. 



It must be understood, however, before going further, 

 that this porosity is not to be confounded with the spaces 

 between the fibres or other constituent elements of organic 

 tissues. The porosity of Dr. Keber is of a much finer kind 

 than this, and is to be sought for in the substance of which 

 the fibres, &c., themselves are composed. To observe such a 

 condition as this, it is obviously requisite that the substance 

 to be examined should be divided into infinitely small por- 

 tions. Several methods of proceeding are indicated by which 

 particles sufficiently small may be obtained for examination, 



1. A very successful method, according to Dr. Keber, 

 consists in the examination of the dusty particles which settle 

 upon glass when left uncovered ; though this mode would 



