a tiark background. Withdraw enough <>f the water with filter paper 

 &O that the cover -hall rest upon them and hold them still. Kind a 

 -pecmien with contractile vacuoles near one edge (not above or 

 bel w). L'nder these circumstances the discharge of the vacule 

 content- into the -nrnunxling hlack fluid is easily seen. Sketch. 

 I- the discharged fluid carried away in any way. or does it remain 

 again-t the surface of the animal? 



f. AV.v pirat ii'ii. '1'his is difficult to observe or demonstrate. It 

 ha- been done in the following way. Make a weak, slightly reddish 

 solution of rosolic acid ( ro-ol ). Place a dense ma-- of I'aramecia in 

 this, on a slide, with a supported cover-glass. < )ften the animal- 

 gather in dense groups. When this occurs, enough carbon dioxide 

 may be given off in the respiration of the large number to decolorize 

 the rosolic acid, \\hen this occurs, if the preparation is placed 

 on a white background the region where the I'aramecia are gathered 

 appears like a white spot in the red preparation. 



Is there any method in 1'aramecium of continually renewing 

 the water that is in contact with the body, so as to have at all 

 times a fresh supply of oxygen? 



250. Types of substances digested. Paramoecia which feed on 

 algae or bacteria must digest proteins. Determine if starch is di- 

 gested, a- f, Hi >ws : 



Add a little dilute corn starch paste to -ome of the organisms in 

 a covered watch-glass. At intervals remove a few Paramecia to 

 a slide and add iodine solution. Does the reaction indicate diijc-- 

 tion of starch? Keep for a day or two and test with i dine again. 



The dige-tion of fat is difficult to demonstrate but it is probable 

 that Paramecium contains lipolvtic cn/.vme-. 



Pi. A.Moi-.r.A. 



It material and time permit, make a study of the same pn>ce--es 

 in Amoeba. If you are unable to see the facts yourself, read the 

 references jjiven below. Komi an idea of the way each of the 

 processes mentioned on pp. ~2 and 73 occur. 



251. a. The (akin;/ of finnl. This can n-uallv be observed, 

 with -ome patience, in a culture where Amoebae are numerous. 

 If ob-crved, describe and sketch. If you do not -ee it yourself, read 

 the accounts given in the following: 



( arneiMe Institution. Publication i<>, Jenning-: Contributions to 

 the Studv of the Behavior of the Lower < )rganisms. pp. IIJ^-JDJ. 



l.ridy. Kre-h water RhlZOpods of \orth America, pp. S^-Xij (in 

 I >inamoeba. \\hicb is practical!) an Amoeba I. See also Plate VI. 



