STUDIES IN EARTHWORM CHLORAGOGUE. 93 



in the earthworm such a crude method of waste elimination is 

 further supported by the results of an experiment performed by 

 a fellow student at Lake Forest College, Mr. John J. Jackson. 

 His experiment was undertaken to learn how the earthworm 

 eliminates a foreign substance injected into the ccelomic cavity. 

 Lamp-black was the substance used on this occasion. Histolog- 

 ical preparations of material thus treated showed the lamp-black 

 evidently making its way through the tissues of the outer body 

 wall to the outside in the manner described for the waste 

 chloragogue granules. That the letter are thus directly extruded 

 any one may easily demonstrate by the following experiment : 

 A thrifty worm thoroughly washed is placed under a bell-jar and 

 subjected to the influence of ether vapor. The mucus which 

 the worm casts off as a result of this ether vapor irritation, on 

 microscopical examination is seen to contain an abundance of 

 chloragogue granules which are enveloped or embedded in a 

 transparent substance possibly the contents of a mucous or a 

 leucocyte cell that soon bursts, allowing the granules to scatter 

 in various directions. 



In the waste masses, for the most part composed of chlora- 

 gogue granules, found in the anal region are large numbers of 

 setae, in one adult worm as many as six hundred and twenty- 

 five (counted in part and estimated) were present, varying in size 

 from small undeveloped to large fully developed ones. The size 

 of the setae depends somewhat on the size of the worm the fully 

 developed setae naturally not being found in a very young worm 

 while in an adult worm both very small and fully developed setae 

 are often present. Also in many of these same waste masses are 

 found nematodes Aiignilnla luinbricd, kindly determined for 

 me by Dr. VV. M. Wood worth. An interesting question arises 

 in regard to the presence of these nematodes embedded in the 

 waste masses in the posterior region of the body because of the 

 following conditions. While some waste masses are entirely 

 lacking in nematodes, such masses being of a dark brown color, 

 other waste masses again are found which vary from a brown to 

 an almost white color depending on the number of nematodes 

 present. If they are many, in which case the granules of chlora- 

 gogue as a rule are scarce, the masses are white. The question 



