80 GENERAL ANATOMY OF THE GLANDULAR SYSTEM. 



divided very suddenly into branches so small that they could not 

 readily be seen by the naked eye.* 



Notwithstanding these reasons for supposing that the excre- 

 tory ducts of glands were dlerived simply from the arteries of 

 those bodies, it is said that the late Dr. W. Hunter used to 

 declare his belief, that there was a part in glands which was not 

 injected in his preparations ; and to say farther, that he 

 believed his preparations were injected as minutely as those of 

 Ruysch. 



All of these opinions have been strenuously controverted by 

 the Italian anatomist, Mascagni, who believes that the arteries 

 terminate only in veins ; and of course that they neither form 

 exhalent vessels, nor communicate with the excretory ducts of 

 glands. His idea of the structure of glands is different from 

 those either of Malpighi or of Ruysch. 



He supposes that glands contain a great number of minute 

 cells ; that the arteries, veins, and absorbent vessels are spread 

 upon the surface of these cells, in great numbers, and very 

 irregularly. From these cells very small canals originate, 

 which unite to form the small branches of the excretory ducts. 

 According to his idea, the secreted fluid is discharged through 

 pores or orifices of the blood-vessels, into the cells, and proceeds 

 from them through the canals, into the branches of the excretory 

 ducts. Absorbent vessels, in great numbers, originate from these 

 cells. 



In his great work on the absorbent system, when treating on 

 the termination of arteries and the commencement of veins, 

 (Part I, Section 2,) he asserts, that if the kidneys are success- 

 fully injected with size, colored with vermillion, and then 

 laid open by a section of a razor, it will be found that the size 

 without the color has passed into cells which are very numerous ; 

 that the arteries and veins are ramified most minutely on the 

 surfaces of these cells, and that the tubuli uriniferi, as well as 

 the absorbent vessels, originate from them. 



He supposes that a considerable portion of the fluid thus 



* See Experimental Inquiries, vol. ii. p. 178. 



