228 



Profs. Percy Frankland and Marshall Ward. 



to be of its usual character; as far as mineral ingredients are con- 

 cerned, it is but little removed from distilled water ; it contains, how- 

 ever, just about the same proportion of organic matter as Thames 

 water, although the smaller yield of albuminoid ammonia and the 

 larger amount of oxygen absorbed from permanganate show this 

 organic matter to be qualitatively different. In point o£ fact, the 

 organic matter in Loch Katrine water is almost exclusively of peaty 

 origin, whilst that in Thames water, coming as it does from land 

 which is under high cultivation, is derived from a variety of sources, 

 both vegetable and animal. 



The Loch Katrine water was also experimented with in three 

 different states : (a) in the natural condition unsterilised, (b) sterilised 

 by filtration through porous porcelain, and (c) sterilised by steam. 



The method of infection was similar to that already described for 

 Thames water; the sporiferous anthrax bacilli were taken from an 

 agar-agar cultivation of four days' age. Eight needle loops full of 

 the surface growth were introduced into 50 c.c. of sterile water, and 

 thoroughly mixed by violently shaking for 15 minutes ; 1 c.c. of this 

 attenuation was then employed for infecting 750 c.c. of each of the 

 three waters. 



The waters, after infection, were distributed in a number of small 

 flasks, which were then disposed of as follows : — 



t -i -rr i • ; r»i i -j f 3 flasks in refrigerator (6 — 10° C). 

 Loch Katrine water, unnltered . ,° „ ~ . 



13 „ incubator (18 — 20 (J.j. 



Loch Katrine water, filtered f 3 „ refrigerator. 



through porcelain 1 3 ,, incubator. 



Loch Katrine water, steamed . . / ^ " yefrigeiator. 



IS ,, incubator. 



Gelatine plates were in each case poured on the day of infection, 

 and also on several occasions subsequently, after the lapse of various 

 intervals of time. The results of these examinations will be found 

 in the following Tables XII, XIII, and XIY :— 



