372 Dr. Barry's further Remarks on the Muscularity of Cilia, 



with one another ; and secondly, as our attention was directed 

 to two very different things, that it was still less possible for 

 any of them to agree with me. Hence a main cause of dis- 

 cordant views on the structure of the muscular fibril. 



LVI. Further Remarks on the Muscularity of Cilia. 

 By Martin Barry, M.D., F.R.S. and R.S.E.* 



[With a Plate.] 



THE Philosophical Magazine for August and September 1852 

 contains the substance of a paper of mine which had been 

 translated into German from the English MS. by Prof. Pur- 

 kinje, Foreign Member R.S., and communicated by him to 

 Mulleins Archiv for 1850; confirming by renewed inquiries, 

 made in his house, the observations I had recorded in the Philo- 

 sophical Transactions eight years before (1842) on the spiral 

 structure of muscle, and announcing the muscular character of 

 cilia. It was in bivalve Mollusca and in Infusoria that I saw 

 the latter. 



Arisen like independent beings each in its own cell or ovum, 

 and endowed with contractile power, cilia of the Mussel's gill 

 were shown to grow and pass through stages of development 

 both in action and in form; and at length, when matured, 

 and not till then, to combine in large numbers for the 

 production of a current. A pellucid membranous canal, appa- 

 rently destined to absorb oxygen from the water, was seen to 

 exhibit on each side a phalanx of cilia (Plate V. fig. 10 n, o) ; 

 while the extremities of these, arching over, united to form an 

 avenue through which by their vehement undulatory vibrations 

 to drive a stream, and thus arterialize the blood. It was further 

 shown that young cilia (m, in the same figure) are continually 

 arising to take the place of those that drive the stream; the 

 latter, when worn out, being one after another cast off and 

 swept away by that same stream, to be succeeded, as just said, 

 by fresh generations, which produce and in their turn undergo 

 like changes. My observation of continued renewal of muscular 

 fibrils in the ever-acting heart, was thus confirmed by what I 

 subsequently saw of continued renewal among incessantly vi- 

 brating cilia. 



I have now to add, that, arising coil-like from the nucleus of 

 a cell, the young cilium pushes forth the cell-wall, as in the out- 

 line fig. 8, to some little length before the extremity is free, 

 often giving to its cell the flask- or retort-like appearance I for- 

 merly described as produced in blood-cells of one of the Am- 



* Communicated by the Author. 



