EPITHELIUM OF THE MUCOUS MEMBRANE. 483 



ceased in the epithelium of the surface of the mucous mem- 

 brane, but when no cilia were visible. 



He states that the best mode of observing the ciliary move- 

 ment is to carefully break up with needles portions of the 

 membrane excised with scissors, in iodized serum, aqueous 

 humour, or a one per cent, solution of common salt. 



The vibrations of the cilia are usually extremely lively, 

 though of very variable duration ; in the Mouse and Cat, for 

 instance, ceasing after a few minutes, but persisting under 

 similar conditions under a covering glass, in the Sheep, for an 

 hour or more. 



The direction of the strokes of the cilia, as seen in optical 

 longitudinal sections of the glands, is constantly from their 

 fundus towards the orifice, whilst in optical transverse sections 

 a vortex is formed, producing the appearance of a screwlike 

 line. 



Observations of the appearances presented at different planes 

 in one and the same tube are easily effected by proper focus- 

 sing, especially in the Cow, on account of the numerous and 

 often very sharp coils it makes in its course. In order to 

 obtain separate cells with' quiescent but well-preserved cilia, 

 Lott spread out a portion of the cornu of the uterus of the Sheep, 

 either fresh or after being kept in iodized serum, in such a 

 manner that he could scrape the surface rather firmly with a 

 convex scalpel without cutting it. By this means the epithe- 

 lial tubes of the glands can be squeezed out free from all sur- 

 rounding connective tissue, and the cells may often be seen 

 quite undisturbed in their position. Small fragments of the 

 tube frequently appear in transverse section upon the slide, 

 so that here also the most diverse sectional planes can be looked 

 at coincidently. Such specimens should be examined either 

 in iodized serum, or in a cold saturated solution of bichromate 

 of potash, which renders the cells very transparent, and brings 

 out the nuclei and contour lines with very sharp definition. 

 He never observed vibration of the cilia in such preparations, 

 nor in those macerated in iodized serum, and the quescient cilia 

 had undergone some alterations, yet they were sufficiently dis- 

 tinct to enable him to state that they were extremely short and 

 fine, and that they stood in close apposition to one another. 



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