SMALL-POX AND VACCINIA 261 



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 Measures. — As already stated, 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 small-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 mast be detained at a quarantine 

 station for a period of eighteen days after the last exposure 

 to infection. All bedding and clothing in the infected 

 house must be thoroughly disinfected, as far as possible, 

 by a steam-disinfector. The house itself must be well 



