214 Dr Barry on Fissiparous Generation. 



39. I long since performed the experiment of Miiller, — that 

 of filtering the fresh-drawn blood of frogs, and thus removing 

 its corpuscles. After some time, a gelatinous substance was 

 found in the filtered fluid ; but I could discern no fibres in it. 



Fmiparous Reproduction of the Muscular Fibril. 



48. I have met with states of the muscular fibril, which, in the 

 first place, shew that here also is to be recognised the fissipa- 

 rous mode of reproduction ; and, secondly, may perhaps ex- 

 plain the cause of the great diff*erence between the observa- 

 tions of some others on this tissue and my own. 



49. I saw a double spiral (Plate V. fig. 2, a) — the formed and 

 contractile muscular fibril — dividing into two rows of pellucid 

 particles of hyaline (^), apparently nuclei, that had been con- 

 tained within the substance of the interlacing spirals (fig. 3), 

 and were now enlarged. In another instance (fig. 2), the nu- 

 clei of each row (7) were dividing (b) and forming new spi- 

 rals (g). One fibril appeared thus, by fissiparous generation, 

 to be giving origin to two. 



50. The particular mode in which a row of nuclei becomes 

 a spiral thread, I have not with certainty ascertained ; and can, 

 therefore, do no more than offer the following as probable, 

 and as being in accordance with what I have seen elsewhere. 



51. Nuclei, by elongating, form contractile cilia ; and fila- 

 ments are seen proceeding from nuclei in opposite directions.* 

 Were filaments, thus formed by each half-nucleus (fig. 2, 5) 

 of two adjacent rows, to assume the spiral form and interlace, 

 and the filaments of the same row to then unite, we should 

 have the double spiral. (The oblique position of the two rows 

 of half-nuclei in fig. 2 3 is not undeserving of notice here.) 



52. There is another subject to which I ask particular at- 

 tention in connexion with the properties above mentioned 

 (par. 13) as inherent in the hyaline — the subject of fissipa- 

 rous reproduction of the Infusoria. 



53. The Infusoria compared with Cells. \ — Between the ap- 



♦ See Phil. Trans. 1841, Plate XXII. fig. 115, in which filaments of "cellu- 

 lar" tissue will be found delineated as thus forming. 



t [On the subject of the generation of the Infusoria, Professor Owen remarks : 

 '« With regard to the more common fissipai'ous mode, Ehrenberg has figured 



