574 STATE BOARD OF AGRICULTURE. 



experimeut, tlieu the amounts of carbon dioxide and ammonia driven 

 off by distillation were very nearlv equal— the average difference being 

 only 0.38 c. c. 



Experiments No. 4 and 5 show that where ammonia but no carbon 

 dioxide was present in the air at the end of the experiment, considerably 

 more ammonia than carbon dioxide was driven off in the process of 

 distilling the beetles. 



No, 4 was the only trial out of the six recorded here where the 

 ammonia was used strong enough to render the beetles apparently dead 

 at the end. In the other trials the beetles became more or less help- 

 less within ten to fifteen minutes after the ammonia gas was applied 

 (sometimes the only signs of life wouild be a slight twitching of the 

 antennae) but in every case, except Nos. 4 and 5 where ammonia was 

 still present, recovery was quite noticeable before the experiment was 

 ended. 



The presence of ammonia in sufficient amounts to kill the. insects — 

 enough remaining over uncombined to render the water in which they 

 were distilled decidedh' alkaline — did not cause the insect-tissue itself 

 to yield ammonia. That is, no more ammonia was driven off than had 

 been used in the process of treating the insects. Three experiments, not 

 recorded in the table, were especially directed to determine this last 

 point. The three special trials were carried out because one other ex- 

 periment indicated that such might be the case, but its result seems 

 undoubtedly due to some mistake — most likely to a mistake in the 

 amount of -j^- sulphuric acid used in "C." 



The various results in this connection, therefore, point strongly to 

 the following conclusion : Part of the ammonia gas in air confined with 

 specimens of P. cornutus is rapidly absorbed by them. Some of this 

 absorbed gas appears to unite with carbon dioxide in their bodies at 

 once. If the amount of ammonia is not high enough to kill, carbon 

 dioxide continues to be formed slowly and to unite with the ammonia 

 in the tissues. As this process goes on, more ammonia is slowly ab- 

 sorbed from the air by the tissues until finally almost none remains. 

 Carbon dioxide, produced by the insects after that, begins to be given 

 off in the respired air. Unlike the other insecticide vapors already dis- 

 cussed, it will be seen, the infiueuce of ammonia is to reduce the value 

 of the respiratory ratio. Enough ammonia gas to render insects help- 

 less reduces both their intake of oxygen and their production of carbon 

 dioxide, but the reduced respiratory quotient shows that the carbon 

 dioxide prodriction is reduced most. 



Since from specimens which were treated long enough for all the 

 ammonia to be used out of the air, ammonia and carbon dioxide were 

 distilled off (at about 212^ F.) in equal volumes it would appear that 

 they had been united in the tissues in the form of bicarbonate of am- 

 monia. 



Vernon^ in IDOG, using ammonia in Ringer's solution with mammalian 

 kidneys fuund that the respiratory quotient was depressed — the more 

 concentrated the ammonia the more rapid the diminution in the quotient. 



He tried hydrocyanic acid also, among other poisons, and found that 

 it caused a slight rise in the respiratory quotient of perfused kidneys. 



'Venioii, II. M. .lounial of Phy.s. Vol. 35, page 53. 



