Gf. H. F. Nuttall 
451 
usually done in the drying process that follows upon the cutting off of the 
steam from the inner chamber after steam sterilization has been effected. 
Vondran's apparatus constitutes a distinct advance in hot-air dis¬ 
infection. In this apparatus air heated either by a furnace or by electricity 
is forcibly propelled through clothing and effects contained in a chamber. 
The heated air thereby overcomes the low heat conductivity of the 
clothing and expels the cold air confined in the interstices of fabrics, both 
of which factors render disinfection by stagnant hot air inefficient. 
Experiments by Rautmann (1915) 1 led the engineer Vondran to 
perfect his apparatus. Rautmann found that he could disinfect leather, 
paper, catgut, etc., by this means. Kutcher (1916) 1 , working with a small 
apparatus, found that typhoid bacilli were destroyed therein at 70-80°, 
but at times survived an exposure at 90° C. Baerthlein (1916, p. 527) 
worked with a large apparatus that was used with very satisfactory results for 
destroying lice at Czersk Prisoners’ Camp. This apparatus had a capacity 
of 6-45 cbm. and was capable of dealing with 45 complete soldiers’ kits at 
a time; it took 10 minutes to heat up to 80-85° C., this temperature being 
maintained for 25-30 minutes. Baerthlein found some spore-free bacteria 
to be capable at times of resisting 95-100° C. for 2 hours. Miessner and 
Lange (1917, pp. 329-365) on the other hand destroyed anthrax spores 
by an exposure of 2 hours at 125° C., but contrary to Rautmann they 
failed to sterilize catgut satisfactorily. 
The discrepancies in the results above recorded are doubtless ex¬ 
plained by the circumstance that if the apparatus is incompletely or not 
uniformly filled, the air, following the course of least resistance, streams past 
the objects and out through the chamber without penetrating them 2 . 
Moreover, as I have already noted (p. 450), damp effects must first 
become dry before they can attain the requisite temperature. The 
experimenters state that in a well-filled apparatus the objects near the 
hot-air inflow become more highly heated than those above, the difference 
between the top and bottom of the chamber at times amounting to 
20° C. In the empty apparatus the temperature in all parts is very 
uniform, but a slight obstruction in the chamber upsets this uniformity. 
If the hot-air supply is cut off the temperature soon becomes equalized 
again in the chamber. The higher temperature of the fabrics situate near 
1 Cited by Miessner and Lange (1917, pp. 332, 333), originals inaccessible: Rautmann 
(1915), Untersuchungen iiber den Desinfektionswert stark bewegter, trockener Heissluft. 
Centrathl. f. Bakteriol. Orig. Lxxvn. 56. Kutcher (1916), Priifung des Vondran’schen 
Entseuchungsapparates, Munchm. med. Wochenschr. p. 337. 
2 The same phenomenon may occur in steam disinfectors. 
