'376 Dr. Barry's Account of the Discoveries of Keber 



phatics measured j-^j^js'", those of the serous did not differ from 

 those of the mucous membranes ; the pores of the bones and 

 teeth in cases which I examined, measured from TTniij'" *^ ttt^oo'"' 

 In respect of all other details I once more refer to my repeatedly 

 mentioned paper. 



The physiological and pathological conclusions following the 

 above mentioned facts require, for the reader acquainted with 

 his subject, no more than a short intimation. As from the 

 results of my examinations the vascular membranes are not 

 " hermetically closed," but porous quite through, — as even the 

 walls of the capillaries arc not " structureless,'^ but consist of a 

 network of the finest filaments and plates, between which the 

 microscopically perceptible and measurable spaces form a system 

 of the finest hollows and interstices, — the physiological processes 

 of endosmosis, exosmosis, absorption, nutrition, and secretion, 

 now appear to us as a natural consequence of this physiological 

 and mechanical constitution of the vascular membranes. It 

 consequently follows from the above discovery — which, proceed- 

 ing by the methods I have given is not difficult to confirm — 

 that in all organic textures there are present and optically de- 

 monstrable those microscopic openings, without which the most 

 important vital processes must always appear incomprehensible 

 to the natural understanding. By this demonstration there 

 falls one of the most important bounds through which the 

 doctrine of a change of material had so much of the tottering 

 and hypothetical, and a long and on-many-sides sought positive 

 foundation for the understanding of most organic processes has 

 now been shown to admit of objective demonstration. 



That the cell-membrane of plants is by no means structureless, 

 but is composed of the finest filaments, has very recently been 

 demonstrated by Agardh*, who has thereby confirmed the re- 

 presentation given by Martin Barry in 1842. v 



Further, I would call to remembrance the fact, that through 

 the objective demonstration of the microscopic pores already 

 formed in all animal membranes, the penetration recently shown 

 by G. Newport t of the spermatozoa into the frog's ovum seems 

 to find its natural explanation, seeing that the spermatozoa, 

 possessing no perforating organs at their fore-end, are incapable 

 of boring through a poreless membrane; whereas, with the 

 presence of preformed pores, even a yielding together of the 

 texturC'elements and an enlargement of the natural pores through 



* De cellula vegetabili fihrillis tenuissimis context a, Lundse, 1862, page 

 8. — See Proceedings of the Royal Society of London, March 17, 1853. 



t Phil. Trans. 1853, p. 271, Note. — The penetration of the spermatozoa 

 into the Rabbit's ovum had been discovered by Martin Barry ten years 

 before. (Phil. Trans. 1843.) 



