Zl^ Ralph S. Lillie 



treated with incredulity Delage's account of successful experiments 

 with higher temperatures, ascribing the results to the effects of 

 agitation and not of simple elevation of temperature. In Greeley's 

 own experiments ''when great care was exercised in handling the 

 eggs not a single segmentation was produced." The criticism, 

 however, was ill-founded, for it was clear from Delage's papers^ 

 that his eggs were exposed to the high temperatures at a time- 

 namely, early maturation — when agitation is quite ineffective 

 in producing parthenogenesis. It is not until the eggs have been 

 mature for sometime that this result appears;^ while warming, as 

 Delage expressly affirms, is most effective during early matura- 

 tion stages. In Greeley's second paper he again cites Delage's 

 experiments, but without comment. Evidently his intention was 

 to return to the subject. 



Since the appearance of Delage's papers in 1901 there seems 

 to have been Httle further investigation of the influence of rise of 

 temperature in exciting development of unfertilized eggs. The 

 theoretical possibility that development could thus be induced was 

 incidentally adverted to by Loeb*^ some years later: if the sperma- 

 tozoon acts by introducing positive catalysers into the egg, thus 

 accelerating the chemical processes on which the initiation of devel- 

 opment depends, a similar acceleration with similar consequences 

 ought to follow simple elevation of temperature. Loeb has also 

 more recently emphasized the importance of the temperature 

 factor in the production of parthenogenesis by the use of hyper- 

 tonic solutions.^ But no further experimental contributions have 

 appeared toward the solution of the question whether — and under 

 just what conditions — elevation of temperature can in itself initiate 

 the development of unfertilized eggs. The a priori probability 

 that such would be found to be the case must have seemed strong 

 when the high temperature-coefficient of the acceleration of chem- 

 ical processes was considered: a five or sixfold acceleration of at 

 least certain of the reactions occurring in the egg-substance would 



^Delage: Comptes rendus, cxxxiii, p. 348, 1901; Archives de zoologie experimentale et generale, 

 3me Ser., ix, p. 285, 1901. 

 ^ Mathews: American Journal of Physiology, vi, p. 142, 1902. 

 * J. Loeb: University of California Publications, Physiology, vol. ii, p. 158, 1905. 

 ^ J. Loeb: Biochemische Zeitschrift, vol. i, p. 183, 1906. 



