An Intracellular Toxin of the Typhoid Bacillus. 77 



The ordinary manifestations of life cease at zero, but at - 190° C. 

 we have reason to suppose that intracellular metabolism must in addi- 

 tion practically cease — as a result of the withdrawal of two of its 

 ^cardinal physical conditions, viz., heat and moisture. It is difficult to 

 form a conception of living matter under this new condition, which is 

 neither life nor death, or to select a term which will accurately 

 describe it. 



In previous experiments it was found that the photogenic bacteria 

 preserved their normal luminous properties after exposure to the 

 temperature of liquid air. On re-thawing, a rapid renewal of the 

 photogenic properties of the cells occurred. The light is apparently 

 produced by a chemical process of intracellular oxidation. The 

 feasibility of triturating micro-organisms at the temperature of liquid 



. air has now been experimentally established in the case of the typhoid 

 bacillus and other bacteria.* The effect of such mechanical trituration 

 at the temperature of liquid air on the luminous properties of the 

 photogenic bacteria has now been tested. The experiments have 



. shown that the effect of such a trituration is to abolish the luminosity 

 of the cells in question. 



This points to the luminosity being essentially a function of the 

 living cell, and dependent for its production on the intact organisation 



- of the cell. 



I am indebted to Professor Dewar for valuable suggestions, and to 

 Mr. Sydney Rowland and Mr. J. E. Barnard for their assistance in the 

 ♦ experiments, which were carried out at the Jenner Institute of Pre- 

 ventive Medicine. 



" An Intracellular Toxin of the Typhoid Bacillus." By Allan 

 Macfadyen, M.D., and Sydney Rowland, M.A. Commu- 

 nicated by Lord Lister, F.R.S. Received August 14, 1902. 



The existence of a specific toxin produced b}^ the typhoid bacillus 

 has hitherto not been demonstrated, although it has been assumed by 

 .analogy with other organisms and by reasoning from the clinical 

 course of the disease. 



Such a poison must either be intracellular or extracellular. 

 That it does not exist in filtered cultures of the organism is the 

 • common experience of bacteriologists. Its absence from such cultures 

 .might be due, however, to unsuitability of the soil used for growing 

 the organism. 



# The Intracellular Constituents of the Typhoid Bacillus," Allan Macfadyen 

 -and Sydney Rowland, ' Centralblatt f. Bakteriologie,' vol. 30, 1901, No. 20. 



