82 



MARY GRACE SPRINGER. 



Several experiments were performed using instead of extracts, 

 water in which eggs had developed. As above specified, " bias- 

 tula water ' ' is understood to mean water in which eggs have 

 developed to the blastula stage. Details of these experiments are 

 not given because the results do not differ in any way from those 

 obtained by the use of such water as indicated in the above tables. 

 If a relatively large amount of blastula water, i.e., 15-20 c.c. to 50 

 c.c. of sea water is used, a very slight retardation is noticed when 

 the culture is compared with the control. If only very small 

 amounts of this " water " are employed no perceptible retardation 

 occurs. Since these results seemed to indicate that possibly the 

 retardation in the case of the eggs developing in the blastula 

 water, for example, was due simply to an insufficient supply of O 

 in the water together with increased acidity, boiled sea water was 

 substituted for the blastula water. A very slight retardation was 

 observed not so evident by any means as that seen in the controls 

 employing blastula water, and quite within the limits of ex- 

 perimental error. This decrease in the degree of retardation, 

 however, may have been due in part, at least, to a decrease in the 

 number of bacteria present in the cultures made up with the boiled 

 sea water. 



Since in all the experiments it was quite evident that there was 

 a shorter length of life in the cultures in which extracts were used, 

 an experiment was made using extracts of suspensions which had 

 been boiled previous to being centrifuged, and comparisons drawn 



Series 36. 

 TABLE V. 



