4- HAROLD SELLERS COLTON. 



writer has been unable to procure the form in question. As no 

 direct experiments on the nature of the fluid contained in the 

 ducts and .mipull.i- have in this case been possible, the writer 

 has'resorted to indirect means that of the use of certain in- 

 \ it am stains. 



In the use of these stains the writer has not proceeded far and 

 hopes at another time to undertake a fuller discussion of their 

 -i-mtu -.mce. Suffice it to say that certain dyes, when introduced 

 into the blood of a living organism in solution, have affinities 

 for formed substances in the cells of certain tissues, as methylene 

 blue in nervous tissue. Others, such as neutral red, act as 

 indicators, telling us whether a given substance has an acid re- 

 action or not, while still other dyes are segregated out of the 

 blood as solids and deposited in cavities often connected with 

 the exterior. 



Following the experiments of Chrzonszezewsky ('64), Heiden- 

 hain ('74)' by injecting certain dyes, principally indigo carmin 

 and ammonium carminate, into the veins of vertebrates came to 

 the conclusion that tin- former dye was excreted by the Malpig- 

 hian tubules of the kidney, while the glomeruli excreted the car- 

 minate. Kowalewsky ('89) carried this idea into his experiments 

 on invertebrates, concluding that renal cells show either acid or 

 alkaline reaction which determines the character of the secretion. 

 However, Schmidt ('cji) 2 has shown this idea false, as both am- 

 monium carminate and indigo carmin may lie excreted by the 

 same organ. Nevertheless, it is a rather general characteristic 

 of renal organs that they excrete carmin in some form. 



In this study of Botrylliis the writer has placed colonies in 

 neutral red, in Bismarck brown, in ammonium carminate and 

 in indigo carmin, studying the reaction of the pyloric gland to 

 these dyes. Neutral red in concentrations rendering the sea 

 \\ater a pale yellow, stain- i he secretion in the re IN of" the organ 

 an intense red and colors the liquid in the lumen of the <lnct- and 

 ampnll.r also. The probable -i-niln MIICC of this is that the secre- 

 tion has an acid reaction. Ui-marck brown coloring the water 

 much like that of the neutral red, stains the granules brown and 



I IKIMI I'.i nut /. ' 



