REVIEW 513 



traps on the tops of some of the tallest poles in the vicinity, and 

 he will soon be a captive. When killed and hung up in the centre 

 of the plant, he serves as a warning to keep others away. 



With poultry plants located in the immediate vicinity of large 

 centres of population, there is increased danger of theft. Appre- 

 ciating this fact, the great majority of commercial poultry men 

 keep well-trained watch dogs about the plant. In some cases they 

 run at large; in others, they may be chained to their houses, or 

 probably the best practice is to have them located about the border 

 of the plant on long wire trolleys, which will allow them to cover 

 a considerable area. Many poultry breeders are dog breeders as 

 well, often getting a considerable revenue from this side-line. 



Modem Disease Control. — During the past few years marked 

 progress has been made in the control of a number of our most 

 dreaded poultry diseases. Notable among these is the work of 

 Rettger, Conn., in developing the blood agglutination test for 

 white diarrhoea. By this method it is possible to test the blood 

 of the breeding hens, and those hens affected ^nththe organism can, 

 as a result of the reaction, be detected and killed, leaving the re- 

 maining birds ^ree from the disease and a safe breeding proposition. 



Recently the work of Beach of California in developing a 

 vaccine for the control of chicken-pox has marked a definite step in 

 advance. It is possible to manufacture a vaccine which, when in- 

 jected into the birds, mil act not only as a preventive against 

 chicken-pox, but it will also aid in stamping out an attack if ad- 

 ministered during the early stages of the epidemic. 



REVIEW. 



1. What is fundamental to a practical knowledge of poultry diseases? 



2. Under what conditions is it desirable to treat diseased poultry? 



3. When is it not desirable to treat diseased poultry? 



4. Discuss prevention as compared with curing. 



5. Give three factors essential in maintaining a healthy flock. 



6. Define the word hygiene as used in this chapter. 



7. What three practices are essential to insure clean houses? 



8. Give the composition of a complete disinfecting solution, and tell of its 



effects. 



9. Discuss the effects of sunlight and of moisture in their relation to a sani- 



tary and hygienic house. 



10. Discuss clean feeding. 



11. What is the best practice to guarantee clean yards? 



12. Describe the external appearances of sickness, associated with many 



disorders. 



13. Give external symptoms of roup; tuberculosis; chicken pox; gapes. 



33 



