Jan. i9,1924 
Influence of Low Temperatures on A scans Eggs 
171 
alkalis, ammonia was tested by Kobayashi (5). Yoshida ( 11 ) had found 
that eggs were unable to develop in urine, and according to Kobayashi 
this was interpreted by K. and S. Minagawa as the effect of ammonia 
formed from the urine. His results showed, however, that eggs survived 
more than a month in urine and for several days in ammonia (1 to 4 per 
cent). Salt solutions have little or no effect on the development of 
Ascaris lumbricoides eggs, Galli-Valerio (j) having obtained embryos in 
saturated solutions of copper sulphate, iron sulphate, copper acetate, 
and 50 per cent antiformin. He states that the eggs are destroyed after 
four months in pure antiformin. Ransom and Foster (8) found that the 
latter dissolved the shell of the egg but left a thin membrane around the 
embryo which would protect it from the action of the antiformin for at 
least five days. According to Kobayashi (4) eggs will develop in a 
saturated solution of sodium chlorid, but the embryos will die when 
they become mature. 
Dilute formalin solutions and also a 10 per cent potassium bichromate 
solution have proved to be excellent culture media for Ascaris eggs, as 
they have no ovicidal action and they keep the bacterial count low. 
According to Kobayashi (4) and also Yoshida (jj), motile embryos will 
develop in a 10 per cent formalin solution but will not do so in solutions 
of 20 per cent or higher concentration. 
Embryos in eggs kept by Ransom and Foster (8) in crude petroleum 
and in petrolatum were still active after 5 weeks; after 10 weeks those 
in the petrolatum were dead, but those in the crude petroleum still alive. 
With regard to the phenols, these writers state that they kept eggs of 
Ascaris lumbricoides containing embryos alive for several hours in carbolic 
acid. However, reports of Wharton (9) and Yoshida (jj) were to the 
effect that the embryos do not develop in a 0.5 per cent solution. This 
is in accord with Wigdor’s results, as stated above, with Toxascaris eggs. 
The present study was made with*phenol solutions in order to deter¬ 
mine in great r detail their ovicidal properties and the practicability 
of their use as disinfectants in the control of Ascaris. It w s felt that 
experiments, to be of practical value, must app oximate conditions 
found in pig pens and that the disinfectant itself and the method of its 
application must be such as can be used there. Hence relatively pure 
ultures of eggs totally immersed in soluti ns of disinfectants would be 
valuable only to the extent of indie .ting the possibility of the use of 
these disinfectants under practical conditions. A disinfectant not 
proving efficacious under such ideal experimental conditions would 
certainly not prove so in practice. Therefore experiments were carried 
out with pure cultures covered with the disinfectant in a beaker and then 
those concentrations of the disinfectant which had proved ovicidal 
under these conditions were used for further tests in which conditions 
were made to simulate those often found in pig pens of sanit ry construc¬ 
tion : the eggs were well mixed with sawdust and the latter sprayed with 
the disinfectant. 
To determine the relative resistance of Ascaris lumbricoides eggs at 
different stages in their development, cultures of fresh, of partially 
developed, and of completely developed eggs (i. e., containing active 
embryos) were used. The cultures were prepared by squeezing the eggs 
out of the uteri of the worms, covering them with a 2 per cent formalin 
solution and keeping them in an incubator at a temperature of 20-24° C. 
until the desired stage of development was reached. 
