77 
delicate organism and a very resistant one, it is highly pro- 
bable that all the delicate organisms would have disappeared 
before any great number of the very resistant organisms had 
succumbed to the action of the sun. 
It may be objected that, if we intend to formulate any 
law as to the viability of bacilli, this law must obviously 
apply to all specimens of the same variety in whatever situa- 
tion they may be found in nature, otherwise the statement 
is of no value in itself. We have no intention of laying 
down any hard and fast rules, for our experience teaches us 
that such do not exist in nature. We are quite content with 
the very widest generalization, provided these are based on 
observations from nature, and on the results of experiments 
carried out as nearly as possible under natural conditions. 
Imperfect as these experiments are, they are amply sufficient 
to prove the correctness of certain wide conclusions. These 
conclusions may be of great importance to the water analyst. 
Experiment No. it. 
A mixture of five samples of human feces— 
Emulsion before exposure contained .. I coscoroba, 9 Grunthal. 
After 1 hour’s exposure showed sm 4coli communis, 2 Grunthal, r 
lactis erogenes, 2 neapolitanus, 
I No. 101, 
,, . 2% hours’ 3 re -- 4Cloaez, 3 coscoroba, 1 lactis 
erogenes, I acidi lactici, 
tn! aoe Mf by ce 8 cloaca, 2 coscoroba. 
aa ae aC + -. 7 Cloace, 2 coscoroba, 1 Grunthal. 
Noon of second day showed (after 10 hours’ 
exposure) wee % I cloace, I coscoroba, 1 No. G7 
Grunthal. 
At 5 on the second day showed -- 10Grunthal. 
Subsequent samples proved sterile in 20 cc. 

Note.—The prevalence of Grunthal to commence with ; appearance of 
coli communis after 1 hour’s exposure and disappearance entirely before 
2 hours ; usual appearance of cloace and great predominance until near the 
end when bacillus Grunthal survived all others ; important comments are 
made on this result in the succeeding part of this chapter. 
There is another point that requires discussion. In 
the results given in Experiment 11, on the emulsion being 
put into the sun 9 Grunthal and 1 coscoroba were present. 
