The Journal of experimental zoology . 8-85(n) 10-29fn) Fig. 3 Arcella dentata. Complete pedigree of family 26. For descriptionsee figure 1. in hay infusions were more yellowish in color than normal, andthose fed on material collected from a spring-water fish pond atCold Spring Harbor, Long Island, were characteristically pale. Arcella thus resembles the many other organisms that aremodified by changes in the environment; they remain so as longas they are in this environment, but return to their former con-dition when transferred back to the original medium. THE ADDITION OF ALCOHOL One of the s
The Journal of experimental zoology . 8-85(n) 10-29fn) Fig. 3 Arcella dentata. Complete pedigree of family 26. For descriptionsee figure 1. in hay infusions were more yellowish in color than normal, andthose fed on material collected from a spring-water fish pond atCold Spring Harbor, Long Island, were characteristically pale. Arcella thus resembles the many other organisms that aremodified by changes in the environment; they remain so as longas they are in this environment, but return to their former con-dition when transferred back to the original medium. THE ADDITION OF ALCOHOL One of the substances to which Protozoa have been found tobe resistant is alcohol. Experiments were begun to determinethe effects of alcohol on Arcella dentata, but were terminated 436 ROBERT W. HEGNER because of lack of time to keep them going. Sufficient datawere obtained, however, to prove that these organisms are ableto live and reproduce in a medium containing from to 1 percent of alcohol. Three offspring were obtained from one of the. Arcella dentata. Family 14. Camera-lucida sketches (X 207) : A = the original progenitor; with sixteen spines and diameter of 34 units. B = the first offspring after A was placed in a solution of one drop of sodiumsilicate to 50 cc. of normal medium. C = the third offspring of A, produced while A was in a solution of one dropof sodium silicate to 100 cc. of normal medium. D = fourth offspring of A, produced immediately after A was transferredfrom the sodium silicate solution back to normal medium. E = seventh offspring of A, produced immediately after A was transferredfrom normal medium to sodium silicate solution. F = a specimen of the seventh generation after continuous subjection tosodium silicate. specimens that was kept in a per cent solution of alcohol;two of these and the parent were still alive thirty-five days afterthe experiment was begun. The rate of fission was very slow,probably because of the effects of the alcohol upo
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1919
