774 MODE OF SPKEAD OF INFECTIVE DISEASES. 



Method of 

 heating. 



Construction high and 80 cm. wide. The smaller, which costs with acces- 

 sory apparatus about 7 10s., is employed when portions of 

 clothing or linen are to be disinfected (as in tuberculosis) ; 

 the larger, which costs about 13, serves for the disinfection 

 of beds, mattresses, &c. The apparatus is made of tin, with 

 the exception of the bottom, which is copper, and has a conical 

 shape, enlarging at the lower part so as to increase the 

 heating surface. The receptacle for the water is provided 

 with a tube projecting outwards, through which it is filled, 

 with a pressure gauge tube, and with a stop cock to empty it. 

 To provide air-tight fittings for the lid, and also at the 

 attachment of the body of the machine to the boiler, these 

 parts fit into grooves which are filled with water. To prevent 

 cooling, the body and the lid are protected by a thick layer of 

 clay, which is fixed on by means of gauge bandages, and an 

 external arrangement of wire netting. In the lid there is a 

 tube for a thermometer, and another for the steam, with 

 which a long leaden tube is connected so as to conduct the 

 steam out of the house. 



The apparatus is heated by gas. In the case of the larger 

 apparatus twelve large Bunsen burners are necessary to raise 

 the temperature of the thermometer in the lid to 100 C. within 

 half an hour ; for the smaller apparatus five burners are 

 sufficient. This method of heating has the advantage that it 

 can be very cheaply fitted up, that the temperature remains 

 constant, that the heat is very completely utilised, and that 

 the disinfection is completed in a very short time (within 

 two hours). The cost of the gas for the larger apparatus is 

 about sixpence per hour, that for the smaller about 2|d. 

 Where larger machines are employed boilers and fires are of 

 course indispensable. 



Attempts have been made to add arrangements to warm 

 the clothing, &c., previously, and to pass a current of dry 

 hot air through them subsequently to the disinfection in 

 order to dry them as quickly as possible. These arrange- 

 ments have not, however, acted well, and they lengthen the 

 Prevention of process too much ; they are besides quite superfluous if care 

 wetting^of the j s taken to prevent the materials from coming in contact 

 with the water. If the materials are only moistened by the 

 current of steam they dry in a very short time, within half 

 an hour ; and it is only at those places where the water has 

 soaked in that the moisture remains longer and that the 

 colours are more readily destroyed. Hence in the apparatus 

 described above special care has been taken that the water 

 condensing on the walls or top of the apparatus shall not run 

 on to the materials which are being disinfected. Beds and 

 similar bodies are placed in a cylindrical basket of strong 



materials. 



