608 



BR SUTHERLAND SIMPSON ON 



In April and May 1909, in the Physiological Laboratory at Cornell University, two 

 more experiments were made with incubating and control hens. A large wooden box 

 placed on its side, with open front, was divided by a partition into two compartments 

 of equal size, each about two feet high, with a floor space of a little over four square 

 feet. On April 7th a " broody " hen (A') was set on a uest containing eight eggs in 

 one compartment, and a control hen (B') of the same age and breed (Barred Plymouth 

 Rock) was closed in the other compartment by a door of wire-netting. The room was 

 small and dimly-lighted from a single window, and the ventilation was not all that 

 could be desired. A' left the nest occasionally to feed, and B' was allowed to come out 







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Pig. 2. — Chart showing temperature curves from A (interrupted line, brooding) one week after hatching out chicks, and B 

 (continuous line, control), May 30th and 31st. The 24-hour range in A is now greater than in B. 



of the box and move about in the room for an hour or two daily, but was always shut 



in again at least one hour before the temperature was taken. 



On April 11th another pair of hens (Barred Plymouth Rock) were secured, one (A") 



" broody," the other (B") normal as a control. A" was set on a nest with eight eggs in 



a corner of a large and well- ventilated room adjoining the small room mentioned above, 



and B" was given its freedom in the same room. 



In these two experiments, which were conducted in the animal house attached to the 

 laboratory, the rectal temperatures were recorded daily at 9 a.m., noon, and 6 p.m. 

 regularly, and on four occasions — April 13th-14th, 20th-21st, 27th-28th and May 4th- 

 5th — readings were taken every three hours throughout the twenty-four. The figures 

 (degrees centigrade), together with the room temperature, are given in Table II. 



As no chicks appeared under A' at the end of twenty-one days the eggs were opened, 

 and three were found to contain dead chicks. The remaining five were unfertilised ; 

 three of them had been broken in the nest. On April 30th A' and B' were turned into 

 the larger room along with A" and B". On May 1st and 2nd six chicks were hatched 



