216 APPLIED BACTERIOLOGY 



one of the most infectious of the specific fevers. The virus 

 exists in the blood, in the contents of the eruptions, in the 

 dry scabs, and in the excretions and secretions of the 

 patient. The poison clings tenaciously to all articles of 

 clothing, particularly woollen goods. 



The usual incubation period is twelve days, but it may 

 be delayed to the seventeenth or eighteenth day; on the 

 other hand, it may, if inoculated, be as short as seven days. 

 After the incubation period the well-known and character- 

 istic symptoms appear, the rash usually appearing on the 

 third day after the onset, though cases are recorded where 

 it did not appear till the fourth day. 



Preventive Measxires. — Vaccination, while it does not give 

 in every case an absolute immunity, very greatly diminishes 

 the susceptibility, and, if an attack does take place, modifies 

 its violence very considerably. 



As the infection of small-pox is undoubtedly carried by 

 the air for considerable distances, it follows that all small- 

 pox patients should be treated in a special hospital, situated 

 as far as possible from crowded centres, and that the 

 ambulances used for the conveyance of smaU-pox patients 

 should be reserved for them alone. Much more energetic 

 action is taken in Australia than in this country in the 

 carrying out of preventive measures against the spread 

 of small-pox, with the result that the disease is practically 

 unknown there. The following are some of the chief points 

 on which stress is laid : All who have recently come into 

 contact with a small-pox patient must be re -vaccinated, 

 unless this has recently been successfully done, or they 

 have previously had an attack of small-pox. All members 

 of the infected household must be detained at a quarantine 

 station for a period of eighteen days after the last exposure 

 to infection. All furniture, books, bedding, and clothing in 

 the infected house must be thoroughly disinfected, as far as 



