Sb'2 Education and Eesearch in Poultry Keeping. [Dec, 



is not exliausted. Much less is kno\Yn, however, of the effect oi 

 parasitism as contributing to or even initiating disease. Dr. 

 Bradley referred to an interesting investigation which has been 

 concluded by Theobald Smith, into Entero-hepatitis or *' black- 

 head " of turkeys. 



Though research should be mainly concerned with disease, 

 there are other abnormal conditions that olfer a profitable field 

 for investigation. Physiology, particularly the physiology of 

 digestion and nutrition, and the laws of heredity, were men- 

 tioned as subjects in which research is needed. 



Research in Incubation. — Mr. Tom Xewman, in his paper on 

 Research in Incubation, said that the dead-in-shell problem 

 remained much as it was 10 years ago. It is probable that 

 other factors apart from incubation were partly responsible. Init 

 the immediate problem was the hatchable egg that did not hatch. 

 Xo solution could be offered, but if dead-in-shell could be reduced 

 by 10 per cent, an enormous saving would result. 



The structure of the egg should be understood. First there 

 was the shell, consisting of calcium carbonate or lime, with 

 just a trace of inorganic materials. The shell is porous, and 

 slow evaporation takes place, while, during the growth of 

 the embryo, carbon-dioxide escapes and oxygen is taken up. 

 Observations have been made on the loss of weight during 

 incubation, and conclusions have been drawn indicating that 

 brown-shelled eggs, which are less porous and of a closer 

 texture than white, are more difficult to hatch. Inside the shell 

 are two membranes : one remains in close contact with the shell, 

 while the inner membrane, following the shrinking of the con- 

 tents, usually separates from the outer membrane at the lar<je 

 end, forming the air cell. These membranes permit gases to 

 pass through them when moist, but if dry become impermeable. 



Graham incubated eggs for one week under hens and finished 

 the hatch in incubators, and also incubated the first week in 

 incubators and finished under hens. 



Those started under hens gave satisfactory lesults. but the 

 other group showed no improvement as compared with eggs incu- 

 bated artificially during the whole period. Here the problem 

 can be narrowed down to one of temperature. It does not seem 

 that moistiu'e on the intake of oxygen materially affects the 

 development of the embryo. Under a hen the eggs are warmed 

 by being in direct contact with the source of heat. The tem- 

 perature of an incubator is not evenly distributed, and it may 

 be that during the fi.rst few days a number of germs are weakened 

 by insufficient heat. The variation, between the centre and 



