PHYSICAL AGENTS 



131 



to 60° and by "retarders" is kept at this temperature for 

 twenty to thirty minutes (Figs. 94 to 97) . In another type the 



Fig. 89. — Steam chambers in hold of U. S. quarantine station barge "Pro- 

 tector." Disinfected space. 



fiG. 90. — Municipal disinfecting station, Washington, D. C, 



