293 The Ducts of the Human Submaxillary Gland 



the elastic fibres was limited solely to the main duct, whereas by means 

 of improved elastic tissue stains we can show that these concentrically 

 arranged elastic fibrils embrace ducts of all orders as high as those which 

 drain the lobules. 



According to the Tobiens '" the ducts of the glands in general con- 

 sist of connective tissue. Those of the salivary glands in addition 

 possess muscle fibres, which are arranged in an outer longitudinal and 

 an inner circular layer. All the ducts of man, horse, dog, and cat have, 

 according to this investigator, elastic fibres which vary inversely with 

 the amount of muscle present. The arrangement of the fibres is in- 

 constant, but there is usually an inner circular layer, while in man 

 spirally arranged fibrils situated outside of this layer can occasionally 

 be found. The results of Tobiens' work, however, has never been con- 

 firmed. 



Krause " describes the ducts as consisting of fine-meshed connective 

 tissue with numerous longitudinal or transversely-running elastic fibres. 

 With the exception of Wharton's duct, muscle fibres do not occur in 

 the walls of the submaxillary ducts. Previous to the work of Henle ^^ 

 the epithelium of the Ductus submaxillaris has always been described 

 with a single layer of epithelium. He states definitely, however, that 

 the epithelial lining of Wharton's duct is made up of a double row of 

 cells. This observation has now been shown to be true of all the ducts 

 of the extralobular system as well. 



Von Ebner " supports the work of Pfliiger on the structure and nature 

 of the salivary tubes and describes, for the first time, the intercalary 

 ducts. These, he states, are clothed by cubical epithelium and form 

 that portion of the excretory system between the alveoli and the salivary 

 tubes of Pfliiger. 



This fact was emphasized by Klein " and Heidenhain." Klein des- 

 cribed the epithelium of the ducts of the human submaxillary as con- 

 sisting of an inner layer of cylindrical cells with long nuclei and a 

 deeper layer of small cells with oval nuclei. In his later paper Klein 

 goes extensivel}^ into the origin and relation of the ducts. Among 

 other things he states that the amount of connective tissue supporting 



"Tobieus: De slanclularum ductibus efferentibus ratione imprimis habita te; ae 

 miiscularis. Inaiig. Diss. Dorpat, 1853. Cited by Oppel. 

 11 Krause: Zeit. f. rat. Med. Bd. 31, 1864. 

 '■^ Henle: Eingeweidelehre, 1871. 

 13 Von Ebner: Arch. f. milv. Anat., Bd. VIII, 1872. 

 " Klein: Quar. Jour, of Mic. Science, N. S., vol. XIX, 1879. 



Klein: Quar. Jour, of Mic. Science,, vol. XXII, 1882. 

 '5 Heidenhain : Hermann's Handbuch d. Physiologic, Bd. V, 1880. 



