Ciliary Motions in Reptiles and Warm-blooded Animals. 115 



tubes in mammalia, and of the air-passages in both. A trans- 

 lation of their memoir is here given, to which I beg to subjoin 

 an account of the results which I obtained on repeating some of 

 their observations. 



I may previously mention, however, that in a paper publish- 

 ed in 1830,* I pointed out the existence of the motion in ques- 

 tion in the larva of the frog and salamander, in most of the 

 tribes of mollusca, in the annelida, and in the actinia, and en- 

 deavoured to shew that it was a provision extensively prevalent 

 among aquatic animals ; serving chiefly to maintain a flow of 

 water along the surface of their respiratory organs, but in some 

 cases also to convey food to the animal, discharge the ova, or 

 assist in locomotion. The distinguishing characters of this mo- 

 tion were, 1st, That the fluid was moved along the surface of the 

 parts in a determinate direction ; 2d, That the impelling power 

 resided in the surface over which the fluid was conveyed, which in 

 most instances, or, as I have reason from subsequent observa- 

 tions to conclude, in all, is covered with moving cilia ; 3d, That 

 the property continues for some time in detached portions of the 

 tissue, in which case the impulsion of the fluid takes place in the 

 same direction with respect to the surface of the parts, as before 

 their separation. 



At that time I was not aware of any similar observations, ex- 

 cepting those of Dr Grant and others, on the Infusoria and 

 Zoophytes ; but I have since found, that in some of the facts I 

 have been anticipated by previous observers. The currents on 

 the gills of the tadpole, and larva of the salamander, were pre- 

 viously described by Steinbuch.-J- His work, which I first 

 saw in the library of Professor Rudolphi, in Berlin, in 1831, 

 seems to have been little known, at least his discovery did 

 not attract the attention it deserved ; and, with one or two 

 exceptions, it seems to have escaped the notice not only of 

 general physiological writers, but even of those who have spe- 

 cially written on the development of the Batrachia, on the 

 continent as well as in this country. Observations similar to 

 those of Steinbuch seem, however, to have been made by 



* Edinburgh Medical and Surgical Journal, vol. xxxiv. 

 •f Analecten neuer Beobachtungen und Untersuchungen fur die Natur- 

 kunde. Furth. 1802. 



H 2 



