416 ANATOMICAL AND rATIIOLOGICAL OBSERVATIONS. 



cells. Between the nucleus and the cell-wall is a light-brown 

 fluid, with one or two oil-globules floating in it. 



The vesicular creca in the testicle of Sqiiahis cornubicus 

 contain nucleated cells, which nltimately exhibit in their 

 interior bundles of spermatozoa. 



The o-enerative cceca of EcJiiurus vulgaris (Lamark) contain 

 cells full of minute spermatozoa. 



Ai^lysia ^)«wcteto secretes from the edge and internal 

 surface of its mantle a quantity of purple fluid. Tlie secreting 

 surface of the mantle consists of an arrangement of spherical 

 inicleated cells. These cells are distended with a dark purple 

 matter. 



The edge and internal surface of the mantle of Janthina 

 fragilis (Lamark), the animal which supplied the Tyrian dye, 

 secretes a deep bluish purple fluid. The secreting surface 

 consists of a layer of nucleated cells, distended with a dark 

 purple matter. 



If an ultimate acinus of the mammary gland of the bitch 

 be examined during lactation, it is seen to contain a mass of 

 nucleated cells. These cells are generally ovoidal, and rather 

 transparent. Between the nucleus and the cell-wall of each 

 a quantity of fluid is contained, and in this fluid float one, 

 two, three, or more oil-like globules, exactly resembling those 

 of the milk. 



In addition to the series of examples already given, I 

 mio-ht adduce many others to prove that secretion is a function 

 of the nucleated cell. Some secretions, indeed, are so trans- 

 parent and colourless, as to render ocular proof of their 

 original formation within cells impossible ; and we are not 

 yet in possession of chemical tests sufficiently deKcate for the 

 detection of such minute quantities. The examples I have 

 selected, however, show that the most important and most 

 striking secretions are formed in this manner. The proof of 

 the universality of the fact, in reference to the glandukr 



