CILIA. 



631 



The ciliary motion in the mouth and throat 

 occurs all the way from the opening of the 

 mouth to the termination of the oesophagus. 

 Its extent and the direction of the impulsion 

 are easily ascertained by means of powdered 

 charcoal ; they are pointed out by the arrows 

 in the adjoining figures, A and B (jig. 311), 



Fig. 311, 



Salamander. 



which are taken from the Newt, the ap- 

 pearances in the Frog and Toad being not ma- 

 terially different, a is the lower jaw detached 

 from the head, b the tongue, c the glottis, 

 d the oesophagus cut off from the head (at g, g, 

 Jig. B), and laid open from above, e the sto- 

 mach, and_/j/^ the lungs. The general course 

 of the impulsion, or, if in this case we might 

 so express it, the currents, is longitudinal ; they 

 begin at the symphysis of the lower jaw and 

 extend to the lower end of the oesophagus, 

 where they terminate abruptly at the entrance 

 of the stomach, thus differing from the de- 

 scription given by Purkinje and Valentin ; but 

 it is worthy of notice that these observers de- 

 scribe the motion in the Tortoise and Serpent 

 as extending the whole length of the oesopha- 

 gus. At particular parts the impulsion fol- 

 lows the direction of the plaits of the lining 

 membrane. Figure B represents the head and 

 the roof of the mouth, from which the lower 

 jaw has been separated. On this part of the 

 mouth also the general course is longitudinal, 

 from before backwards; at the nostrils h, h, 

 the particles are drawn in at one edge and issue 

 at the other, as indicated in the outline of 

 figure B. 



As regards the use of the ciliary motion on 

 the internal membranes of the Batrachia, we 

 can scarcely doubt that one purpose is to 

 convey onwards the secretions of these mem- 

 branes in the direction indicated. It is not 

 impossible also that it may have some more 

 intimate connection with the respiratory pro- 

 cess; but on this point we have not as yet suf- 

 ficient grounds for forming a probable opinion. 



Sanria, Ophidia, and Chelonia. The authors 

 mentioned describe the appearances in these 

 reptiles as being similar to what they have 



found in Batrachia. The ciliary motion oc- 

 curs in the oviduct and in the nose, mouth, 

 pharynx, Eustachian tube, and inner surface 

 of the lungs. In the Serpent and Tortoise they 

 state that it extends along the gullet to its 

 termination at the stomach, as we have seen to 

 be the case in the Balrachia. The motion of the 

 cilia is remarkably vivid in the mouth of the 

 Serpent, and in the Tortoise it endures for 

 several days after death, not ceasing till the 

 parts are destroyed by putrefaction. 



B. Birds. The same physiologists have 

 discovered the phenomena in thirteen species 

 of Birds, belonging to five different orders ; 

 and as they met with it in every species sub- 

 mitted to examination, they infer that it exists 

 in all. 



In Birds, as in otherVertebrated animals, the 

 motion shows itself on the lining membrane 

 of the oviduct and that of the respiratory 

 organs. It was detected in the nasal cavities 

 and Eustachian tube, in the windpipe and its 

 divisions, even in the smallest branches capable 

 of investigation, and on the internal surface 

 of the large sacs or receptacles into which the 

 air penetrates. No trace of it could be found 

 in the mouth and pharynx. In regard to the 

 direction of the impulsion, the authors state 

 that in the oviduct they had found it to be 

 from the internal towards the external extre- 

 mity of the tube, and in the windpipe from its 

 oririce towards its branches, or from without 

 inwards, at least they so observed it once in 

 the domestic Fowl. The phenomenon exists 

 in the fetus of the bird, having been distinctly 

 seen in the fetal pigeon near the full period. 



C. Mammalia. An accidental observation 

 led Purkinje and Valentin to discover the 

 ciliary motion in Mammalia, and they fol- 

 lowed out that discovery by extending their 

 inquiries to other vertebrated animals. While 

 examining the Fallopian tube of a rabbit that 

 had been recently impregnated, in order to 

 discover the ova, they chanced to observe 

 small portions of the mucous membrane of 

 the tube turning round, and moving briskly, 

 and recognized the appearance as an instance 

 of ciliary motion. The whole uterus and 

 organs of generation generally were then dili- 

 gently searched, and these motions were dis- 

 covered throughout their entire extent, though 

 of very different degrees of intensity in dif- 

 ferent places. They were particularly brisk in 

 the tubes, less so in the cornua of the uterus, 

 still less in the conjoined parts of the organ, 

 most lively of all on its swollen and dark red 

 lips, and of considerable strength in the vagina. 

 After finding the same appearances in the 

 oviduct of Birds and Reptiles, they succeeded 

 also in discovering it in the lining membrane 

 of the air-passages in all the three classes. 

 In Mammalia the ciliary motion of the re- 

 spiratory organs occurs on the mucous mem- 

 brane of the nose and its sinuses, and that of 

 the Eustachian tube, also on the lining mem- 

 brane of the lower part of the larynx, the 

 trachea, and bronchial tubes, extending to 

 their smallest divisions capable of examination. 

 No trace of it can be found in the glottis, nor 



