292 



HITCHCOCK'S ANATOMY 



fast that it was necessary to dry it off occasionally during the 

 dissection. 



514. Vicarious Secretion, — Another curious phenomenon 

 connected with this subject is vicarious secretion, where one 

 organ performs the whole or part of the office of another. 

 This is often seen in the function of the lungs and liver, where 

 one imperfectly performing its office, is aided by the other. 

 This vicarious secretion is still more apparent between the 

 liver and skin. For in the disease known as Jaundice, where 

 some obstruction is offered to the passage or secretion of the 

 bile, it is poured out by the skin, coloring it deeply yellow, 

 and in some instances it has been known to stain the linen, 

 which is worn next the skin, perceptibly yellow. 



515. Ductless Glands. — In connection with this subject 

 it is proper to mention a class of organs known as Ductless 

 Glands, or bodies which have the form and general structure 

 of glands, but no duct or outlet, and form no secretion, as do 

 the true glands. These are the Spleen, the Thymus and 

 Thyroid Glands, and the Supra Renal Bodies. Of these only 

 the former will be described here, since the latter are most 

 perfectly developed during the earliest, or fetal stage of exist- 

 ence. 



516. The Spleen, — The Spleen measures in different indi- 

 viduals from four to six inches in its longest diameter, and is 

 situated under the left extremity of the stomach. (Fig. 282, 

 p. 293.) It is of a reddish blue color, convex on its external, 

 and concave on its internal surfac \ It is very abundantly 

 supplied with blood-vessels, and consequently vascular or 

 spongy in its structure. (Fig. 283, p. 293,) Upon a close 

 inspection it is found to be made up of corpuscles from one 

 third to one sixth of a line in diameter, each of which is com- 

 posed of nucleated cells about j -jVoth of an inch in diam- 

 eter. (Fig. 284, p. 293.) 



514. State the principle of vicarious secretion What remarkable facts in this connec- 

 tion about jaundice ? 515. Describe the ductless glands. What are their names ? At 

 what period of life are they the most fully developed ? 516. Describe the spleen. 



