9O RICE. 



on either side of the dorsal blood vessel, the chloragogue is 

 found surrounding the origin of the aortic arches dorsally, and 

 covering the dorso-intestinal blood vessels, an important fact, 

 inasmuch as the blood gathers from the alimentary wall into the 

 dorso-intestinal blood vessels and through them flows into the 

 dorsal blood vessel. This condition suggests that the chlora- 

 gogue may with good reason be considered as having to do with 

 food elaboration. The chloragogue is found less abundant still 

 on the outer surface of the alimentary wall, arranged in irreg- 

 ular circular bands. It is also found laterally and ventrally 

 but not as abundantly as on the dorsal aspect. It is entirely 

 absent from the ventral blood vessels, in marked contrast to 

 its abundance on the dorsal vessels. In passing, reference 

 may be made to the fact that within the dorsal blood vessel as 

 seen in cross section a tissue is found, which in appearance, is 

 much like the chloragogue. The largest individual chloragogue 

 cells are found on either side of the dorsal vessel as it crosses 

 the crop and gizzard. The walls of the crop and gizzard are 

 free from chloragogue. 



III. Structure. The typical adult chloragogue cell is club- 

 shaped, having at its narrow base a nucleus of medium size which 

 readily stains, while filling the remaining cell space are innumer- 

 able minute yellow granules which compose the greater part of 

 the cell and give to it its characteristic color, which varies from 

 a brownish-yellow to a yellowish-green. These chloragogue 

 granules are apparently lifeless. No stain has been found to 

 affect them, the strongest acids like nitric acid and hydrochloric 

 acid affect them but slowly. Likewise strong alkalies like po- 

 tassium hydroxide have only a very slow effect in disintegrating 

 them. Neither does feeding or starving a worm, as will be shown 

 later, have any apparent effect upon the chloragogue. In the very 

 young worm, however, the entire chloragogue cell is more or less 

 responsive to stains, and the younger the chloragogue the more 

 striking is its likeness to the peritoneal epithelial layer of which 

 it is generally supposed to be a modification. 



IV. Function. One of the first attempts to determine the 

 function of the chloragogue was through special feeding. A long 

 series of negative results was obtained. The difficulty was not 



