194 



Profs. Percy Frankland and Marshall Ward. 



with sporiferous anthrax bacilli, the latter had been so much re- 

 duced in number, that a whole cubic centimetre of the water, irre- 

 spectively of whether it had been kept at the winter temperature of 

 the refrigerator, or at the summer temperature of the incubator, 

 was unable to cause the death of a mouse, the most sensitive of 

 animals to anthrax. 



It was in the next instance necessary to ascertain whether the 

 sporiferous anthrax had actually perished outright in this water, or 

 whether it was still present in a living state only in very small num- 

 bers. To determine this point, the following plan was adopted : — 

 The two flasks referred to above, 3 I and 3 R, were each treated with 

 5 c. c. of sterile broth on October 15, 1892, and placed in an incub- 

 ator at 37° C, so as to encourage the growth and multiplication of 

 any anthrax bacilli or spores that might still be living in them. With 

 these nourished waters, so to speak, then, the following two experi- 

 ments were made : — 



Animal Experiment No. 16. — On October 18, 1892, 0"4 c.c. from 

 the Flask 31, to which broth had been added on October 15, 1892, 

 was subcutaneously injected into a white mouse. The mouse died 

 within 1 day 19 hours, and, although no bacilli could be microscopic- 

 ally detected in the spleen, a gelatine tube inoculated from the spleen 

 developed a typical growth, and in this the characteristic anthrax 

 bacilli were subsequently found, thus leaving no doubt that the mouse 

 had died of anthrax. 



Animal Experiment No. 24, — On October 29, 1892, 0'5 c.c. from the 

 Flask 3 R, to which broth had been added on October 15, 1892, was 

 subcutaneously injected into a white mouse. The mouse died within, 

 2 days 18 hours ; the spleen was found to be full of anthrax bacilli, 

 and gelatine cultivations prepared from the spleen yielded the cha- 

 racteristic growths, thus leaving no doubt that the animal succumbed 

 to anthrax. 



These two experiments dearly demonstrate that the sporiferous anthrax 

 bacilli had not become actually extinct in this unfiltered Thames water 

 (either at winter or summer temperature), but had only undergone great 

 numerical decline, for on adding broth to the waters these straggling 

 forms multiplied sufficiently to cause the death of the mice which re- 

 ceived subcutaneous injections of them. 



Of subsidiary interest in Table II is the insight furnished 

 into the behaviour of the ordinary water bacteria at the tem- 

 peratures in question. These numbered about 10,000 per cubic 

 centimetre at the outset,* whilst after 4 days (March 22, 1892) about 



* This does not refer to the number present in the water at the time of its col- 

 lection from the Thames, but at the time of its infection witb anthrax several days 

 later. The sample was collected on March 8, and the infection was made on the 

 18th of the same month. 



