378 Ralph S. LiUie 



is sufficient, at the proper time during the maturation period, 

 to produce development. It is not surprising that the eggs failed 

 to develop under these conditions. The general outcome of 

 Greeley's own w^ork on the influence of temperature changes on 

 protoplasm appears to have led him to doubt the possibihty of 

 producing parthenogenesis by elevation of temperature. He had 

 found that cold, by inducing loss of w^ater, exercises on protoplasm 

 an action similar to that of a hypertonic solution, w^hich was already 

 known to produce parthenogenesis; and it must have seemed to 

 him scarcely possible that warmth, which affects the protoplasm 

 in a precisely opposite manner from cold, could have the same influ- 

 ence on the developmental process. It is also evident that his 

 experiments on the action of high temperatures in inducing par- 

 thenogenesis were less complete than those made with cold; 

 evidently his studies of the influence of temperature-conditions on 

 development were cut short while they were yet unfinished. 



II EXPERIMENTAL 



My own experiments were begun in the summer of 1906, at a 

 time when I was unaware that Delage had succeeded in producing 

 development by this means. The idea with which the study was 

 begun was that possibly a slight change in the aggregation-state of 

 certain of the protoplasmic colloids might be a determining condi- 

 tion of development, and that such a change might be induced by a 

 momentary heating of the eggs. Heat coagulation produced by 

 momentary heating followed by rapid cooling was, according to 

 Corin and Ansiaux, a reversible process." Such a slight and re- 

 versible coagulation might conceivably without injuring the egg so 

 change the state of the egg substance as to cause development to be 

 resumed. It soon became evident, however, that even transitory 

 exposure to temperatures of 45° to 50°, the lowest at which heat 

 coagulation could be expected, was rapidly injurious, inducing 

 breakdown of the eggs without any developmental changes. On 

 the other hand, brief exposure to temperatures of 35° to 38°— in 



'1 Corin and Ansiaux: Bulletin de I'academie royale de Belgique, xsi, p. 345, 1891. The results 

 of Corin and Ansiaux have since been rendered doubtful by Pauli: Beitrage zur chemischen Physiologie 

 und Pathologic, x, p. 53, 1907. 



