A GUIDE FOR KEEPERS OF POULTRY 209 
hatch by 17 per cent. Ina room with no ventilation only 
11.9 per cent of the eggs hatched and of these 55.5 per 
cent died the first week. In a well-ventilated room 36.3 
per cent hatched and only 9 per cent died the first week, 
the difference being in the first case 5 1/3 chicks in 30. 
This shows the influence of bad air outside of the incu- 
bator, a trouble easily avoided by free ventilation or pip- 
ing off the lamp fumes. Prof. Graham found that even 
in natural incubation vitality was affected by the way the 
hen was set. The number of chicks alive at the end of 
four weeks was as follows: 
With hens set on the ground...............0. ceeee 62.2 per cent 
With hens set on straw in a bOx...............605. 43.4 per cent 
With hens set in ventilated nest..............:0e0+ 39.1 per cent 
“This shows conclusively that natural secretions from 
the hen’s body—as moisture—must be retained even in 
natural incubation to secure chicks that will live. Where 
the non-moisture incubator was used, run according to 
directions without applied moisture in the egg-chamber, 
while the hatches were fairly good the mortality was 
high, being over 60 per cent of all chicks hatched, while 
the number of chicks alive at the end of four weeks out 
of every 100 set was only 16. These were very good 
eggs, above the average, and these were the results from 
12 tests. By the use of moisture the percentage of living 
chicks from 13 tests was 32:7 per cent. As the hens aver- 
aged 43.7 per cent and 48.7 per cent respectively this 
shows the difference is due to the missing factor in arti- 
ficial incubation, this being carbon dioxide or some other 
volatile agent. By the use of zenoleum, which contains 
volatile carbon compounds that the eggs absorb, prac- 
tical results approximate very closely those obtained by 
natural incubation, and by its use mortality is much re- 
