THE INFLUENCE OF LOW TEMPERATURES AND OF 
DISINFECTANTS ON THE EGGS OF ASCARIS LUM- 
BRICOIDES 1 
By EivOiSE B. Cram 
Zoological Division , Bureau of Animal Industry, United States Department of 
Agriculture 2 
INFLUENCE OF LOW TEMPERATURES 
The results of previous investigations have indicated that the eggs of 
Ascaris lumbricoides are resistant to low temperatures. Wharton (g ) 3 
states that low temperatures retard the development of the eggs but do 
not kill them; Yoshida (ir) reports experiments in which the eggs were 
put on the ground or under a layer of soil and left through the winter 
months in Osaka, Japan, and their infectivity later proved by their being 
fed to guinea pigs with resulting infestation in these animals. Martin (7) 
states that the eggs resist freezing and are viable after being in the soil 
(Nebraska) over winter. In none of the above reports are definite tem¬ 
perature ranges given. Wigdor (10) kept eggs of Toxascaris limbata in 
the refrigerator at a temperature of io° C. and found that their develop¬ 
ment was retarded but that it ultimately proceeded to the formation of 
motile embryos. 
The present study was made to determine more definitely the possible 
effect which exposure to low temperatures may have on the normal de¬ 
velopment of the eggs of Ascaris lumbricoides from the pig. To determine 
the relative resistance of the 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. Such cultures were ex¬ 
posed to freezing temperatures above o° F. (= — 17.7 0 C.) and also below 
o° F., and their subsequent development after restoration to 24 0 C. 
(75 0 F.) studied. The ^purpose of these tests was to determine the pos¬ 
sibility of such eggs resisting such winter weather conditions as would 
prevail in pig pens. 
TESTS TO DETERMINE THE RESISTANCE OF FRESH ASCARIS LUMBRI¬ 
COIDES EGGS TO VARYING FREEZING TEMPERATURES 
Cultures of eggs were put in Petri dishes, just as squeezed from the 
uteri of the ascarids, were slightly moistened and put in freezers. The 
temperature was read two or three times each day. 
The following exposures were made (1 day = 24 hours): 
For 1 day below zero ( — 7° to — n° F.).culture 1. 
For 2 days at zero (—2° to +2 0 F.).culture 2. 
For 5 days: 
Above zero, temperature of 27-28° F.culture 3. 
Above zero, temperature of 8-11° F. culture 4. 
Below zero (—0.5° to — n° F.).culture 5. 
1 Accepted for publication Nov. 19, 1923. 
1 The experimental portion of this study was carried out in the chemical laboratory of Armour & Co. 
at Chicago, Ill., prior to the author’s resignation from that company in October, 1919. This study was 
a joint project of Armour & Co. and the Federal Bureau of Animal Industry, Mr. Paul Rudnick and 
Dr. H. B. Raffensperger, respectively, directing the investigation. The writer takes this occasion to 
acknowledge her indebtedness to these gentlemen for their courteous assistance. 
* Reference is made by number (italic), to “Literature cited”, p. 175. 
Journal of Agricultural Research, 
Washington, D. C. 
(167) 
Vol. XXVII, No. 3 
Jan. 19, 1924 
Key No. A-69 
