1908 1 Ritter-Bailey — Weight of Developing Eggs. 3 



substance in the egg that passes on from one cell generation to 

 the next "without break in continuity .'" 



4. In case it be held that one or both of the assumptions indi- 

 cated in 1 and 2 are justifiable, is it not true that due regard for 

 the principles of conservation of energy and matter puts such 

 assumptions in the category of those hypotheses that are justified 

 only by being made to be themselves tested, i.e., that cannot be 

 legitimately used as supports for other still wider hypotheses 

 until they themselves shall have been proved? 1 



5. Since the egg is surely a body of limited mass, must it not 

 also be a body of limited potential energy? If this be so, and if 

 development is from the outset an operation performed through 

 the auto-consumption of both matter and energy that reaches to 

 the fundamental metabolic processes, can there ever be complete 

 restoration of the living material in the developing organism even 

 after extraneous food is supplied? 



6. If a diminution in weight up to the time of food-taking be 

 an essential phenomenon in the development of the organism, 

 what would be the form of curve that would represent the re- 

 lation between the amount and rate of diminution? Would this 

 curve be the same for all organisms'? Would it have any neces- 

 sary relation to the normal length of life of the particular or- 

 ganism ? 



There is apparently no end to the questions of this general 

 tenor that might be asked, but beyond such as offer points of 

 attack through observation and experiment, they are of doubtful 

 profit. It would seem, however, that with those which do offer 

 such points biologists might well occupy themselves. 



From a methodological standpoint I would call particular at- 

 tention to two facts in connection with such experimentation. 

 (1) The nature of the problems aimed at demands that both the 

 organisms and their conditions be kept as nearly normal as pos- 



1 Since preparing this manuscript it has been suggested by some of my 

 biological friends to whom I have propounded these questions that I am 

 "demanding too much" as regards the hypothesis of a continuous germ- 

 plasm. My reply is that so far at least as this little paper is concerned I am 

 in both letter and spirit, merely asking questions. There is only one ' ' de- 

 mand'' even implied. That is that in biology we shall recognize observation 

 and generalization to be bound together in a wedlock so sacred and indis- 

 soluble that no offense can in reality sever them. 



