The Journal of experimental zoology . he end of the two months while Races 1 and 6 main-tained themselves a few weeks longer. Although Race 5, underthe influence of some unknown condition, disappeared muchsooner than the others, yet its resistance during its early healthyperiod of rapid development was just the same as that duringthe later period of depression. For example^ one experiment on TABLE 7• Paramecium, caudatum Pure line no. 1 TEMPERATURE 37° 38° 39° 40° 41° Totals 37000 618103 545375 480 Number of deaths 480 Percentage dead at given temperature 100 TABLE 8 Param
The Journal of experimental zoology . he end of the two months while Races 1 and 6 main-tained themselves a few weeks longer. Although Race 5, underthe influence of some unknown condition, disappeared muchsooner than the others, yet its resistance during its early healthyperiod of rapid development was just the same as that duringthe later period of depression. For example^ one experiment on TABLE 7• Paramecium, caudatum Pure line no. 1 TEMPERATURE 37° 38° 39° 40° 41° Totals 37000 618103 545375 480 Number of deaths 480 Percentage dead at given temperature 100 TABLE 8 Paramecium caudatum Pure line no. 5 TEMPERATURE 35° 36° 37° 38° 39° Totals 3000 268 Number of deaths • 268 Percentage dead at given temperature 100 TABLE 9 4 Paramecium caudatum Pure line no. 6 TEMPERATURE 36° 37° 38° 39° 40° 41° Totals 1810 0 45500 48500 4856213 292 Number of deaths 292 Percentage dead at given 100 PROTOZOAN differences: resistance to heat 14]. .^_———— Paramecium caudatum Pure line no. t Paramecium caudatum Pure line no. 6 Paramecium caudatum Pure line no. 5 Fig. 2 February 17 (just three weeks after the culture was started)gave these results: At 36° there were 8 deaths in a total of 76At 37° there were 35 deaths in a total of 120At 38° there were 130 deaths in a total of 130 In another experiment on March 30 (during the period ofdepression): At 30° there were 5 deaths in a total of 40At 37° there were 11 deaths in a total of 28At 38° there were 19 deaths in a total of 19 One may see the effect of the depressing influence by comparingthe totals present in the same quantity of the medium on thesedates. Evidently, whatever factor influenced this race in sucha way as to interfere with its development, had no effect on itsresistance to heat. In spite of unfavorable medium, the curvefor Race 5 represents the normal condition of a distinct race or* biotype, and one is led to infe
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1913
