136 L. B. NICE 
second generation could be quickly obtained to compare with the 
first. 
The experiments were started with 30 female and 15 male 
white mice about four months old. They were bought froma 
dealer and guaranteed not to be brothers and sisters. Four hun- 
dred and forty-one young were born of the first generation in 
seven months. ‘Twenty females and 12 males of this number 
were bred at the age of two and a half months, care being taken to 
prevent inbreeding. These had 230 young in four months. 
Five lines were carried; one was given alcohol, another nicotine, 
a third was subjected to the fumes of tobacco smoke, a fourth 
received caffeine and the fifth line was carried for controls. 
Two females and one male were kept in a cage; each female was 
moved to a separate cage before her young were born and remained 
there as long as they were suckling, which lasted from twenty- 
five to thirty days. The cages were of wire mesh 6 inches wide, 
5 inches deep and 12 inches long. 
The regular diet of all the mice was buckwheat, and crackers 
soaked in milk; every few days they were given carrots, grass, 
meat, ete. 
The alcohol line 
The first generation in this line consisted of 6 females and 3 
males, and in the second generation, the offspring of the first, 
of 5 females and 3 males. 
Two cubic centimeters per mouse of 35 per cent alcohol were 
added daily to the crackers and milk of these mice. Instead of 
water they drank 35 per cent alcohol which was placed in bottles 
containing siphons; so the animals drank directly from the bottles, 
and evaporation was prevented. The mice were first given 10 
per cent alcohol which was gradually increased to 45 per cent. 
Thirty-five per cent was found to be a safe medium since stronger 
percentages sometimes intoxicated the mice. 
All the mice in this line except 16 received alcohol, the young 
beginning to take it at the age of three weeks. Sixteen young 
were given no alcohol themselves although their mothers received 
it for sixteen days after the birth of the young. 
