6 INNERVATION. [CHAP. XVI. 



detached, we observe projecting tubular fragments, similar to the 

 cuticular lining drawn out of the sweat-ducts of the skin, when the 

 cuticle is removed after maceration (figs. 79 and 80). In fact, glands 

 apparently identical with the sweat-glands exist in this region in great 

 numbers. They dip down in the recesses of the submucous tissue, 

 among the ramifications of the olfactory nerves; and their orifices are 

 very easily seen, after the general brown coat of epithelium has been 

 detached, lying more or less in vertical rows, the arrangement of 

 which is probably determined by the course of those nerves beneath. 

 They become more and more sparing towards the limits of the olfac- 

 tory region. The epithelium of these glands is bulky, and like that 

 of the sweat glands, contains some pigment. As the duct approaches 

 the epithelium of the general surface, its wall becomes thinner and 

 more transparent; and, in its subsequent course upwards, it is diffi- 

 cult to be traced, for it does not appear to be spiral, or its particles 

 to differ from those which they traverse. We have sometimes seen 

 rods of epithelium, apparently hollow, left projecting from the base- 

 ment membrane, after the brown epithelium has been washed away; 

 and these are perhaps portions of the excretory ducts of these glands. 

 A good injection of the nasal organ in the foetus, both of man 

 and animals, will display a multitude of minute capillary loops upon 

 the surface of the olfactory region, bearing a close resemblance to 

 those of rudimentary papillae. These loops were first pointed out 

 to us two years ago by Mr. Quekett in the foetal pig, and also in the 

 human foetus at its full term; and so clearly did they seem to indicate 

 the presence of true papillae in this region, that we made repeated 

 and close examinations of the recent organ, in order to expose 



their structure, supposing them to be 

 concerned in the sense of smell. These 

 researches, pursued on adult specimens, 

 have been hitherto fruitless; at least, 

 we have found no other evidence of 

 papillae than delicate hollow epithelial 

 processes remaining, after a gentle 

 current of water had washed away 



Di^atedloopingsofthecapillariesofthe ^ P rinci P al Potion of the brown 



ecSi and'ifia^nified 16 Human Fcetus> in ~ epithelial investment an appearance 



too ambiguous to be spoken of with 



confidence. In the human foetuses we have injected, the loops 

 are such as are represented above (fig. 105). The convexity of the 

 loops presents a decided dilatation, being from 5 L ^ tojsVo f an incn 

 wide, while the diameter of the capillary on either side is only 



