376 
Journal of Agricultural Research 
Vol. IX, No. ii 
Table; II .—Quantity of a chemical necessary to kill five houseflies in a i-liter flask in an 
arbitrary time of 400 minutes 
Chemical. 
Quantity 
of 
chemical 
required 
(in 
millionths 
of a 
gram- 
molecule). 
Chemical. 
Quantity 
of 
chemical 
required 
(in 
millionths 
of a 
gram- 
molecule). 
Carbon, bisulphid . 
286. 2 
Salicylic aldehyde . 
I. I 
Benzene . .. 
j 
142 . 2 
Ortho-nitrophenol. 
5- 6 
Toluene . ... . 
^ 0 
147 e 
Ortho-bromtoluene. 
j 
Q. 4 
Chlorbenzene , . . 
/ J 
42. 4 
Para-bromtoluene. 
7 T 
I. 2 
"Rrom hen zen e . 
IQ. 2 
Ortho-cresol ... 
4 * 2 
Phenol . 
j-y. ~ 
IO. 8 
Meta-cresol . 
7.0 
Todohenzene 
6.6 
Para-cresol . 
/ y 
2. Q 
Benzonitrile 
6.4 
Benzyl alcohol . 
O 7 
e. 2 
Anilin . 
c. 2 
Benzoyl chlorid . 
0 0 
7 * ® 
Benz aldehyde . 
7 
Ortho-nitrotoluene . 
2.1 
Nitrobenzene . 
1.8 
Bromxylene (B. P. i9o°-2io° C.) 
3 * 5 
Xylene . 
6.4 
Bromxylene (B. P. 22o°-2 5o° C.) 
i *9 
Para-dichlorbenzene 
14 . O 
Nitroxylene . 
1. 7 
Para-dibrom benzene . 
4 . I 
Furfural . 
20.8 
Ortho-chlorphenol . 
*T 
4-6 
DISCUSSION OF RESULTS 
TOXICITY AND CHEMICAL COMPOSITION 
By a glance at figure 2 it is noticed that all the benzene compounds 
used are more toxic than carbon bisulphid. The introduction of a 
methyl group into the benzene ring decreases its toxicity. This result 
agrees with the findings for higher animals of Wintemitz and Hirsch- 
felder (7) and further studies of Kline and Wintemitz (3). The intro¬ 
duction of a halogen increases the toxicity similar to the results of 
Bechhold and Ehrlich (1), who found the introduction of a halogen in¬ 
creased the disinfection properties of phenol. This fact is true for insects 
whether the halogen is introduced in benzene, toluene, xylene, or phenol. 
One might expect that, as toluene is less toxic than benzene, the halogen 
derivative of toluene would be less toxic than the similar derivative of 
benzene; but such does not seem to be the case. The iodin derivatives 
are more toxic than the corresponding bromin compounds, while both 
are more toxic than the corresponding chlorin derivatives. The di¬ 
substitution compounds of the halogens are more toxic than the mono¬ 
substitutions. The introduction of the cyanogen group does not increase 
the toxicity as much as might be supposed. The aldehyde group greatly 
increases the toxicity; in fact, salicylic aldehyde is the most toxic of 
all the compounds used in the experiments. From this result it would 
be expected that furfural would be much more poisonous than the 
results show it to be. Substitutions in the methyl group of toluene are 
