70 SECRETION. 



The consistence and general appearance of cerumen are 

 quite variable within the limits of health. When first 

 secreted, it is of a yellowish color, about the consist- 

 ence of honey, becoming darker and much more viscid 

 upon exposure to the air. It has a very decided and bit- 

 ter taste. It readily forms a sort of emulsive mixture with 

 water. 



Examined microscopically, the cerumen is found to con- 

 tain semisolid, dark granulations of an irregularly polyhe- 

 dric shape, epithelium from the sebaceous glands, and epi- 

 dermic scales, both isolated and in layers. Sometimes also 

 a few crystals of cholesterine are found. 



Chemical examination shows that the cerumen is com- 

 posed of oily matters fusible at a low temperature, a peculiar 

 organic matter resembling mucosine, with salts of soda, and 

 a certain quantity of phosphate of lime. The yellow coloring 

 matter is soluble in alcohol ; and the residue after evapora- 

 tion of the alcohol is very soluble in water, and may be pre- 

 cipitated from its watery solution by the neutral acetate of 

 lead or the chloride of tin. This extract has an exceedingly 

 bitter taste. 



The cerumen lubricates the external meatus, accumu- 

 lating in the canal around the hairs. Its peculiar bitter 

 taste is supposed to be efficient in preventing the entrance 

 of insects. 



Meibomian Secretion. Yery little is known concerning 

 any special properties of the Meibomian fluid, except that 

 it mixes with water in the form of an emulsion more readily 

 than the other sebaceous secretions. 1 It is produced in 

 small quantity, mixed with a certain amount of mucus and 

 the secretion from the ordinary sebaceous glands attached to 

 the eyelashes (ciliary glands), and the glands of the carun- 

 cula lachrymalis, and smears the edges of the palpebral 



1 ROBIN, op. cit., p. 592. 



