108 



Prof. Moore, Dr. Koaf, and Mr. Whitley. [Oct. 9, 



Usually two gonads from the female, and about half to one gonad from the 

 male were taken, each in a separate tumbler, gently rubbed up with a small 

 quantity of sea-water, and then separated from d&bris by filtering through a 

 coarse piece of muslin. The eggs were somewhat diluted with sea-water, a 

 quantity of sperm added, and a drop of the mixture taken out and examined 

 with the microscope until it was ascertained that the eggs had developed their 

 fertilization membranes. 



A number of tumblers corresponding to the number of controls and the 

 total of the various dilutions of the different chemicals to be tested for their 

 effects upon the growth of the eggs had previously been arranged and 

 numbered. The mixture of fertilized eggs was now diluted to a larger volume 

 with sea-water so as to afford 200 c.c. for each tumbler, and this volume 

 was measured out into each of the tumblers. As rapidly as possible the 

 desired amount of each chemical was added in each case, and the time of 

 starting noted. The progress of development was observed and noted a few 

 hours after starting the experiment, again the following morning, and so on. 



In a few cases instead of diluting the egg-mixture after fertilization to a 

 large volume, the proper amount of sea-water was measured out into each 

 tumbler, then an equal volume of the egg-mixture was added to each, followed 

 by the desired amount of the chemical solution. 



For the purpose of examining the progress of development a dip was 

 taken out by means of a small pipette into a. watch-glass and examined 

 under a low power of the microscope. The state of development of the 

 growing embryo was noted especially with regard to relative rate of growth 

 in presence of the various strengths of the different alkaline and acid 

 solutions. The number of cells was counted in the earlier stages, or the number 

 of cells in an optical section of the circumference of the blastulae in the 

 later stages ; the commencement of ciliary motion was noted, and the stages 

 in the development of the gastula in those cases where the larvae developed 

 so far. Also any irregularities in shape and size of cells in the different cases 

 were noted. 



In certain cases, the progress of any change in chemical reaction was 

 noted by adding indicators in parallel experiments carried out alongside. 

 Interesting results as to the action of the indicators themselves were so 

 obtained. It was found that the reaction to "di-methyl" did not change 

 throughout the experiment, but the reaction to phenol-phthalein, which was 

 faintly alkaline even in normal sea-water at the commencement of the 

 experiment, slowly changed towards the acid side. As it was found, however, 

 that phenol-phthalein even in very small amounts inhibited and caused 

 irregularities in cell-division, the method was adopted of testing quantita- 



