The Injiiieuce of External Factors oti Development 193 



if at all affected at this time, and those in 0.44 m sugar are normal. 

 The eggs continue to show these graded abnormalities in the dif- 

 ferent solutions and when sixty-eight hours old were as follows: 

 All were dead in the three stronger mixtures, and a few short 

 embryos had been formed and were still alive in the LiCl 0.032 m 

 + 0.44 m sugar. In LiCl 0.128 m at sixty-eight hours many 

 were dead but a good number of short embryos were present; in 

 the LiCl 0.032 m 20 per cent of the embryos were almost normal. 

 In the 0.44 m sugar solution the embryos were normal. The 

 result shows that sugar augments the action of the LiCl although 

 the pressure of the mixed solution is less than that in which the eggs 

 usually live. This conclusion seems to me correct for now I realize 

 the improbability that the sugar may have inverted which would 

 thus have exerted twice the pressure supposed; if this were true then 

 all of the solutions would have a pressure higher than that of the 

 sea-water, though still not high enough in themselves to cause any 

 of the above effects as will be readily seen by comparing the pres- 

 sures of sea-water solutions in which the eggs develop normally. 



A reverse experiment was conducted in which the amount of 

 LiCl present in the solution was constant while varying amounts 

 of sugar were added. LiCl 0.032 m was mixed with 0.293 "^' 

 0.44 m, 0.586 m and 0.88 m sugar, and LiCl 0.016 m with 0.293 

 m, 0.44 m, 0.586 m, 0.88 m and 1.253 m sugar. The results of 

 these experiments showed as one would expect from the above 

 that the injurious action of the solutions increased with the amount 

 of sugar present, and moreover the activity of the mixture was 

 always stronger than that of either constituent when used alone. 

 The last point is well illustrated by eggs of forty-eight hours in the 

 solution of LiCl 0.032 m + sugar 0.586 m. All the eggs in this 

 solution have the blastoderm in the form of a ball on the upper pole, 

 only a few are still alive and in these the large bubble-like segmen- 

 tation cavity is present. The osmotic pressure of this mixture is 

 lower than that of sea-water provided that the sugar has not 

 inverted. At this time, forty-eight hours, eggs in 0.586 m sugar 

 solution are all normal, and those in 0.032 m LiCl almost all have 

 their germ-rings three-quarters of the way over the yolks with 

 short embryos formed; some, however, have the germ- ringonly one- 

 quarter or one-third of the way down. 



