﻿AESENICALS. 37 



Table 17. — Relative toxicity ofarnenalrs and. arsmilrs on 4 ajmiirH of iivwln, 19 10. 



Arsenicals and control. 



Commercial acid lead arsenate 

 Laboratory sodium arsenate. . 

 Average for arsenates 



Commercial zinc arsenite 



Commercial Paris green 



'.V^o"""".\\'.\\V"l'."'.'.'. 



Average for arsenites 



Commercial London purple 



Control with food , 



Percentage of insects dead within— 



d -VS. 



91.0 

 99.0 

 95.0 



96.0 

 100.0 

 100.0 

 98.0 

 98.5 



98.0 



11.0 



28.8 

 19.9 



12.5 



30.7 

 38.9 

 IS. 5 

 22.7 



24.1 



0.0 



E-i 



18.1 

 36. 

 27.3 



65.7 

 59.3 

 53.9 

 61.9 



34.7 



0.6 



21.0 

 33.0 

 27.0 



25.0 

 15.0 

 25.0 

 22.0 

 21.8 



11.0 



0.0 



35.3 

 49.3 

 42.3 



50.6 

 52.8 

 55.8 

 48.1 

 51.8 



42.0 





inn. i) 

 100.0 

 100.0 



100. 



100. 

 100.0 



100.0 

 0.0 



IS 



72.8 

 72.2 

 72.5 



37.5 

 85.2 

 86.7 

 72.3 

 70.4 



57.1 



0.0 



§1 



82.2 

 91.4 

 86.8 



99, 

 97.5 

 97.6 



97.7 



92.0 



62.0 

 60.0 



44.0 

 62.0 

 65. 

 57.0 

 54.5 



33.0 



12.0 



78.3 

 81.4 

 79.9 



69.6 

 86.6 

 84.8 

 81.7 

 80.7 



70.5 



90 



Arsenicals and control. 



Commercial acid lead arsenate. 

 Laboratory sodium arsenate. . . 

 Average for arsenates 



Commercial zinc arsenite. 

 Commercial Paris green. . 



do 



do 



Average for arsenites 



Commercial London purple. 

 Control with food 



Percentage of insects 

 dead within — 



10 days. 



0.0 



I? 



fee 



te S 



g'S 



99.3 



100.0 



96.6 



100.0 



98.0 



100.0 



60.9 



100.0 



100.0 



100.0 



100.0 



100.0 



96.6 



100.0 



89.4 



100.0 



94.7 



100.0 



2.6 



23.1 



99.8 

 98.9 

 99.3 



87.0 

 100.0 

 100.0 

 98.9 

 96.5 



98.2 



Toxicity for- 



97.0 

 99.7 

 98.3 



98.7 

 100.0 

 100.0 

 99.3 

 99.5 



99.3 





61.0 

 65.9 

 63.5 



37.0 

 72.0 

 75.2 

 62.5 

 60.8 



5S.6 



66.8 

 76.0 

 71.4 



88.2 

 85.6 

 83.8 

 86.5 



75.6 



39.5 

 47.5 

 43.5 



34.5 

 38.5 

 40.0 

 39.5 

 38.1 



22.0 



66.1 

 72.3 



69.2 



64.7 

 74.7 

 75.2 

 71.2 

 71.5 



63.9 



1 Based on mortalities for third and sixth days only. 



In 1920 experiments similar to the preceding ones were performed, 

 using one lead arsenate, one sodium arsenate, one zinc arsenite, 

 three Paris greens, and one London purple (an arsenate and an 

 arsenite combined). The following data, which are not given in 

 Table 17, were obtained: Silkworms, 2 sets (each of 50); webworms 

 (H. cunea), 1 set (variation 90-136, average 120); tent caterpillars, 

 3 sets (207-507, average 288); and honeybees, 2 sets (each of 50). 

 Table 17 shows that the average percentage of toxicity of the arsenates 

 was 69.2, while that of the four arsenites was 71.5. The toxicity of 

 the arsenites should be 16.2 per cent more than that of the arsenates, 

 providing the toxicity is due to the arsenic, irrespective of its form 

 of combmation. According to the preceding figures, the toxicity 

 of the four arsenites is only 3.3 per cent more than that of 

 the two arsenates. Comparing the toxicity of the four arsenites 

 with that of the lead arsenate, however, it is 7.8 per cent more, 



