298 



Profs. Percy Frankland and Marshall Ward. 



The table shows conclusively that the anthrax was not exterminated, 

 even after eighteen days at either temperature. 



On January 8, the flask kept at 20° C. was heated to 56° C. for 

 twelve hours, and plates made, These plates, after three days' in- 

 cubation at 20° C, showed that anthrax was still present to the 

 extent of from 110 to 230 per 1 c.c. of the water in the flask. 



If the numbers in Tables x, p. 254, and?/, p. 295, are put in the form 

 of curves, the ordinates representing the numbers of bacteria, we find 

 in all cases that there is a large and rapid rise to a maximum during 

 the first four days ; the climax may be reached during the second 

 day, or the third or fourth, but it is always relatively high, and 

 usually soon reached. Then follows an equally rapid fall during the 

 next twenty-four to forty-eight hours, succeeded by a slower one. 



It is interesting to note that the mixed Bacillus anthracis and 

 _E>. fluorescens liquefaciens behave very similarly as a whole at the 

 lower temperature, 12° C, which is not favourable to the anthrax ; 

 but at the higher temperature of 20° C. it looks as if disturbances of 

 various kinds occur which lead to a very different and irregular 

 curve. 



It seems almost certain that temperature is not the only factor at 

 work here, for, although its effects are very distinct, as shown by 

 comparing Tables x, y, and z, there must be other circumstances 

 concurring to account for the very different heights of the curves, 

 and times taken to reach this maximum. 



The extreme rapidity of the main ascent, when once it begins,, 

 suggests that a moment arrives when the ferment actions which 

 must be supposed to render the food materials available are at their 

 best ; if this is so, the sudden fall may well be due to two causes — 

 (1) the exhaustion of the available oxygen, and (2) that of the food 

 materials themselves. 



The actual height of the maximum — i.e., the numbers of bacteria 

 then sustained by the medium — may well be supposed to depend on 

 a number of factors, e.g., the quantity of food materials, especially 

 organic, present in the water, the number of bacteria in the water at 

 the outset, and, of course, the nature of both, being amongst the most 

 important of these. 



Obviously the whole subject is extremely complex, but we are in- 

 clined to think that valuable information could be got by extensive 

 comparative examinations at constant temperatures of waters of 

 known chemical composition infected with definite quantities of two 

 known organisms, the behaviour of which should be studied at in- 

 tervals of twelve hours if possible. 



