Uj JAMES F. AUr.oii \NU liTIIEL L. Kim.\KI. 



an environment of weak vinegar, it i> the sugar rather than the 

 acetic acid which appears to lie the essential element of the 

 medium. 



With the hope of anaK^ing the relations of this organism to 

 its environment, a number ol lines ot investigation have been 

 taken up in connection with tin- reactions of the nematodes 

 to various media and to different food substances. The present 

 paper deals only with the eflect produced on the worms by 

 distilled water. The worms used in the>e experiments were 

 found in rather -tale weak vinegar of an acidity of <S 10 N. No 

 difficulty was experienced in breeding them abundantly in the 

 laboratoi y both in this medium and in cider. Two kinds of dis- 

 ; illed water were employed. One of these was such as is u>ed in 

 the ordinary work of the laboratory. This was distilled in an 

 automatic copper still and will be designated "A." The- >econd 

 water, which will be designated " B." was obtained by distilling 

 the first kind over potassium dichromate and sulphuric acid, con- 

 den-Miig in block tin out of cc.ntact with the air and redistilling 

 over barium hydrate. The first six tenths of this distillate was 

 rejected and the remainder gave an extremely pure sample, 

 CO-j-frec and showing no ammonia reaction i Noler test) even 

 after the lapse ot twelve hours. This water when tested in a 

 conductivity apparatus of the department of physical chemistry 

 gave no measurable conductivity with a resistance of 20,000 

 ohms and may be considered to be practically free from electro- 

 lytes. It was kept in well steamed, hard glass bottles. In each 

 experiment every precaution was taken to remove all traces of 

 the medium in which the worms were living. The \\omis were 

 washed 6 to 8 times with distilled \\ater in a centrifuge 1 , and in tin- 

 cases where the distilled water "B" was used, two or three times 

 more in this. They \\ere then allo\\r<| to remain in the "B" 

 water lor about 24 hours to injure a thorough ringing. Finally 

 they were again washed in pure- \\ater previous to their in-eriion 

 in the new medium. The bottles and tot tube-- ii-M'd to contain 

 the worms in the first two sets of experiments were ol ordinary 

 soft glass and in the latter ones, .^< liolt (ind (lamsscu, Jena resist- 

 ance glass was employed. The --e containers \\ere thoroughly 

 soaked in chromic acid, and previous to n^e were repeatedly 



