ORGANIZATION AND GROWTH 



233 



TAHLK III 



We obtain a better view of these results when we present 

 them graphically. In the curve shown in Fig. 60 of the text 

 the different amounts of salt contained in each 100 c.c. of the 



3 

 FIG. 60 



various solutions are represented on the axis of abscissas, 

 the increase in the length of the animals on the ordinates. 

 \Yc set' that the growth is nil in a 1.3 per cent, salt solution; 

 that it is just perceptible in a 1.6 per cent, solution; that it 

 increases very rapidly with an increase in the concentration, 

 attaining a maximum in a 2.5 p ( >r cent, solution, and then 

 decreases slowly with a farther increase in the concentration. 

 M n. r/ii/iil linear (jroirfli docs not occur in ordinary sea- water, 

 hnl in n/iirlccdl// <lilnf<'<{, scd-irafcr. The meaning of the 

 curve is very simple: the cells of Tubularia must be turgid 

 in order to grow, and this is possible only as long as the 



