588 



lity, and the result showed that in 15 weeks the hens in House No. i, 

 laid an average of 38.8 each, while those in No. 2 laid only 28.5 

 each. The birds therefore did better when the air was changed 

 only five times per hour, and the difference is attributed to the 

 smaller loss of heat by the birds, which shows itself in production. " 



" It is concluded, therefore, that it is desirable that each bird 

 should be allowed 40 cubic feet of air per hour and that this 

 40 feet should be supplied at a reasonably slow rate. Under con- 

 ditions known by experience to be favourable to the birds, the air 

 changes in a large house four times, and in a small house five 

 times, per hour, which appears to be a very suitable rate ". 



<k Dr. Russell observes that it is clearly impossible for the prac- 

 tical man to test the air in his poultry houses and ascertain the 

 amount of carbonic acid present, nor is there any necessity to do 

 this, because, under similar circumstances, the amount does not 

 show a very great variation. The above conditions are all fulfilled 

 in houses of a more or less cubical shape and also in the low types 

 of house, when (a) there is a floor allowing a certain amount of au- 

 to enter from below, e, g, bricks about a quarter-of-an-inch apart 

 covered with peat moss, or spaced boards if the floor is of wood; 

 {) there is top ventilation, two inches being open under the eaves 

 of a high house, or a few large holes bored in the sides if a low 

 house; and (c) each bird is allowed ten cubic feet of space". 



A. BALFOUR. Further observations on fowl spirochetosis. - 



(Jour. Trop. Med. and Hyg. y 12, No. 19, pp. 285-289. London, 

 1909). E. S. R., Vol. XXII, No. 4. Washington, March 1910. 



This is a record of new development of which some of the 

 more important observations are tabulated and illustrative cases 

 described. 



" It has been found that lice (Menopon sp. r) can, in all proba- 

 bility trasmit the disease from the sick to the healthy chick ... In 

 chicks relapses are common . . . The results of inoculations in the 

 case of chicks have differed from those obtained in fowls . . . Ticks 

 (Argas persicus), either as larvae, nymphs, or adults, fed on chicks 

 with acute spirochetosis exhibit the peculiar chromatin granules first 

 described by Leishman in the case of Ornithodoros moubata fed on 

 blood containing Spirochceta duttoni . . . Chicks, inoculated with an 

 emulsion of crushed larvae, showing these granules, but no spiro- 

 chetes, develop acute spirochetosis . . . Pigeons are apparently not 

 inoculable with this form of spirochetosis." 



