412 ANATOMICAL AND PATHOLOGICAL OBSEHVATIONS. 



XXV. SECKETING STKUCTUKES. (PLATES IV. V) 



MALPIGHI was the first to announce that all secreting glands 

 are essentially composed of tubes, with blind extremities.* 

 Mliller, by his laborious researches, has brought this depart- 

 ment of the anatomy of glands to its present comparatively 

 perfect condition.! Purkinje announced his hypothesis of the 

 secreting function of the nucleated epithelium of the gland- 

 ducts, but made no statement to show that he had verified it 

 by observation^ Schwann suggested that the epithelium of 

 the mucous membranes might be the secreting organ of these 

 surfaces.^ Henle described minutely the epithelium-cells 

 which line the ducts of the principal glands and follicles, but 

 did not prove that these are the secreting organs. The same 

 anatomist has stated that the terminal extremities of certain 

 gland-ducts are closed vesicles, within which the secretion is 

 formed, and which contain nucleated cells. Henle has not, 

 therefore, verified the hypothesis of Purkinje, although he is 

 correct in stating that the terminal vesicles of certain gland- 

 ducts are closed.|| It will be shown, that the secretion is not 

 formed, as Henle has asserted, in the closed vesicles, but in 

 the nucleated cells themselves. 



The discrepant observation of BoehmlF and Krause** on 

 the glands of Peyer, were in some measure reconciled by 



* Exercitationes dc Structura Viscerum, 1665. 



t J. Miiller, De Gland. Struct. Penit. 1830. $ Isis, 1838. 



Froriep. Notiz. 1838. || Miiller's Archiv, 1838, 1839. 



U De Gland. Intestin. Struct. Penit. 1835. ** Mailer's A rchir, 1837. 



