428 



STATE BOARD OF AGRICULTURE. 



noted ;i large per cent of inhibition of batching, while in the later ex- 

 ]»erinients, lliere was almost no inhibition from treatments with the same, 

 and also with much stronger chemicals. In order to get further data 

 on Ihe inhibitory power of sulphuric acid, as compared with the other 

 chemicals used, it was decided to repeat this treatment, using tubes of 

 agar instead of slides. 



EXPERIMENT X. 



March 16. 1914, dissected out a large number of egg masses and divided 

 them into three lots. These lots were treated for a few minutes in 1-100 

 H0SO4, I-5OH2SO4, and 1-25 H.SO^, respectivel}^ and then transferred, 

 while still wet, to three tubes of sj'nthetic agar. The results of this 

 experiment are recorded in Table X. 



TABLE X.— ACTIVE LARVAE OBSERVED. 



Treatment March 16. 1914. 



Number of 

 eggs used. 



March 17. 



March 19. 



March 20. 



H2S0i 1-100 

 HiSOi 1-50. 

 HjS04l-25. 



5000 

 5000 

 5000 



Abundant 



Abundant 



Very many 



Abundant 

 Very many 

 Very many 



Abundant 

 Very many 

 Very many 



The results of this experiment would seem to show that even quite 

 strong sulphuric acid solutions have no more of an inhibiting power 

 than the other chemicals used, when the conditions are made the same. 



EXPERIMENT XI. 



This experiment was made for the purpose of determining the rela- 

 tive value of carbon bisulphide. March 20, 1914, about twelve thousand 

 eggs were dissected out from knots on lettuce, squash and tomato roots, 

 and divided into two lots of six thousand eggs each. The first lot was 

 placed in pure liquid carbon bisulphide for a few minutes, and then 

 transferred, while still wet, to a tube of synthetic agar. The second lot 

 was placed on a hollow slide, and the slide was then inverted over the 

 mouth of a bottle of carbon bisulphide. After being exposed to the 

 strong vapor for twenty minutes, the egg masses were transferred from 

 the slide to a tube of synthetic agar. The results of this experiment are 

 given in Table XI. 



TABLE XL— ACTIVE LARVAE OBSERVED. 



Treatment March 20, 1914. 



Liquid Carbon bisulphide 



Vaporized Carbon bLsuIphide. 



Number of 

 eggs used. 



March 21. 



6000 

 6000 



Twelve 

 Many 



March 22. 



Abundant 

 Many 



March 25. 



Abundant 

 Abundant 



From these results it was concluded that treatments with carbon bi- 

 sulphide, such as the above, do not materially inhibit the hatching of the 

 nematode eggs. 



