EXPERIMENT STATION BULLETINS. 



427 



10. Placed the tenth lot in the same lime-sulfur as the ninth lot. 

 After being in this solution for a few minutes, the egg masses were 

 transferred to a drop of synthetic agar on a cover glass and sealed down 

 over a culture slide instead of being placed in a tube of synthetic agar. 



11. Placed the eleventh lot in full strength commercial sulphuric acid 

 for a few minutes, and then transferred it to a slide of agar. 



12. Placed the twelfth lot in 1-100 sulphuric acid for a few minutes. 

 The results of this experiment are given in Table IX. 



TABLE IX.— ACTIVE LARVAE OBSERVED. 



Treatment March 14, 1914. 



Vessel 



No. of 



eggs 



used. 



Mar. 15. 



Mar. 16. Mar. 17. 



Mar. 18. 



Mar. 24. 



1. Formaldehyde 1-100 



2. Formaldehyde 1-25 



3. Formaldehyde 1-10 



4. Formaldehyde 40% 



5. HgClj 1-500 



6. HgCU 1-200 



7. HgCh 1-100 



8. "Blk Lf. 40" full strength 



9. Lime sul. ful! strength. . . . 



10. Lime sul. full strength 



11. H2SO4 fuU strength 



12 H2SO4 1-100 



Tube 

 2000 

 Tube 

 3000 

 Tube 

 3000 

 Tube 

 3000 

 Tube 

 3500 

 Tube 

 2000 

 Tube 

 2000 

 Tube 

 3000 

 Tube 

 3000 

 Slide 

 3000 

 Slide 

 3000 

 Slide 

 3000 



Abund. 



None 



One 



None 

 Very 



many 

 Very 



many 



Many 

 Very 

 many 



One 



None 



None 



None 



Abund. 

 Abund. 

 Abimd. 



None 

 Very 



many 

 Very 



many 



Many 

 Very 

 many 



Ab'und. 



None 



None 



None 



Abund. 

 Abund. 

 Abund. 



None 

 Very 



many 

 Very 



many 



Many 

 Very 

 many 



Abund. 

 Abund. 

 Abund. 



None 

 None 

 None 



None 

 None 

 None 



Abund. 



None active 



Very many 



Very many 



Many 



Many 

 None active 

 None active 

 None 

 None 

 None 



The results of this experiment as a whole, are so different from those 

 of any of the previous tests that one is strengthened in the opinion that 

 the containing vessel must have been a factor influencing the results. 

 From the table, it will be noted that the treatments which allowed little 

 or no hatching were those where sealed slides were used instead of test 

 tubes. The lime-sulfur treatments give a good comparison of the dif- 

 ference due to the vessel used, because all other conditions were about 

 the same. By referring to Experiment IX, it will be seen that the egg 

 masses were all subjected to the same treatment with lime-sulfur, and 

 then 3,000 eggs were placed in a tube of synthetic agar and 3,000 were 

 placed on a drop of synthetic agar and sealed down over a hollow slide. 

 Abundant larvae hatched from the eggs in the tube, while none hatched 

 from an equal number of eggs in a culture slide. The amount of agar 

 used might be considered as an important factor in bringing out the 

 difference in the result, but by referring to the earlier experiments, it 

 will be seen that where one tube, ten c. c, of agar was spread out over 

 a plate, there was about the same inhibitory effect as in the sealed slide 

 with one drop of agar. 



This comparison of the type of vessel used was made for the purpose 

 of trying to account for the great difference between the results obtained 

 in the early experiments and those of later trials. In the early ones was 



