172 
Journal of Agricultural Research 
Vol. XXVII, No. 3 
The two disinfectants used were carbolic acid and cresol, the latter in 
the official compound solution “liquor cresolis compositus.” The for¬ 
mula 5 for this is— 
Cresol .... . cjoo gm. 
Linseed oil. 300 gm. 
Potassium hydroxid. 80 gm. 
Alcohol .. 20 mils. 
Water, sufficient quantity to make. 1,000 gm. 
Unless otherwise stated, the exposure of the eggs to the disinfectant 
was carried out in a beaker, the eggs being covered with a deep layer of 
the solution and left for the stated time. They were then washed several 
times in water, put in Petri dishes with 2 per cent formalin and kept at 
24 0 C. in the incubator. In the tests in which the eggs were mixed with 
sawdust the mixture was spread over the surface of a large flat pan and 
sprayed with an ordinary atomizer. After the treatment the eggs were 
recovered by washing the sawdust several times with water and cen¬ 
trifuging the washings; they were then kept in 2 per cent formalin at 24 0 C. 
Two concentrations of each disinfectant were used: 5 per cent and 1 
per cent of carbolic acid and 3 per cent and 1 per cent of cresol (6 per 
cent and 2 per cent of the compound). Both 5 per cent carbolic acid 
and 3 per cent cresol solution proved very effective in destroying the 
viability of the fresh eggs and of those in the various stages of cleavage 
and in destroying the activity of developed embryos. A 3 per cent cresol 
solution (6 per cent liquor cresolis compositus) accomplished this in 5 
hours and a 5 per cent carbolic acid solution in 10 hours. In the tests in 
which the eggs were mixed with sawdust, thus obtaining conditions 
which may be found or readily established in pig pens of sanitary con¬ 
struction, it was found that when the mixture was sprayed once with 
either of the two disinfectants and then allowed to stand 24 hours, the 
ability of fresh eggs to develop and the activity of developed embryos 
were not always destroyed. However, if the sawdust mixture was 
thoroughly raked over and sprayed four times during the day and then 
allowed to stand over night, the treatment was more effective. Fresh 
eggs lost all vitality during such treatment with either disinfectant. 
With 3 per cent cresol all activity of developed embryos was destroyed, 
and although one active embryo was found directly after such treatment 
with 5 per cent carbolic acid, on the following day there was no activity. 
A repetition of such treatment on a second day assured the destruction 
of all vitality of fresh or developed eggs. 
Fresh eggs and eggs at the intermediate stages of development were 
influenced to about the same degree by the disinfectants, although one 
test indicates that the further development of the latter is more easily 
destroyed than that of the former: 3 per cent cresol solution for 2 hours 
completely stopped the development of the partially incubated eggs, but 
did not do so with the fresh eggs. 
Whereas in the freezing tests it was found that fresh eggs were more 
resistant to low temperatures than those containing active embryos, 
there are indications that the resistance of the two sorts of eggs may be 
reversed in regard to disinfectants: a 5 per cent solution of carbolic acid 
destroyed the vitality of fresh eggs in 5 hours, but embryos showed 
activity after such treatment, although their subsequent life was short. 
6 u. s. dispensatory (20th edition), p. 631. 
