04 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
the clean water and for slight multiplication during the day, these 277 bathers 
introduced in round numbers 3,^00 bacteria per c.c. Therefore each individual 
introduced 12*6 bacteria per c.c. Now, the capacity of the first class bath is 70,00c 
gallons, i.e., about 320,000,000 c.c. Therefore the water removed from the skin 
and hair of each bather in about ten minutes approximately 4,000,000,000 bacteria. 
Truly it is a great and glorious thing to wash, even in a swimming bath, and 
without soap ! 
In the same way, the capacity of the second-class bath being about 100,000,000 
c.c, each bather contaminated the water with 6,000,000,000 bacteria. Now, the bathers 
in the second class are mainly small boys, and the amount of hair and number of 
square inches ot skin on their bodies must be little more than half that of the older 
and bigger bathers in the first class. Therefore it appears that the skin of a small 
boy in the second class is at least twice as dirty as that ot the more respectable bathers 
in the first class. One has only to see the small boy before and after bathing to be 
convinced that this bacteriological deduction is substantially correct. 
The colossal figures just mentioned are rather appalling, but we are convinced 
that they are approximately accurate. One has only to reflect that bacteria swarm on 
the hair, on every particle of epidermis, and in the mouth of every sweat gland to 
realize that the total number upon the human body must be enormous. 
In order to test the accuracy of these figures, the following experiments were 
performed : — 
An ordinary slipper bath was filled with a measured amount of water containing 
a known number of bacteria, the temperature of the water being ioo° F. An individual 
then entered the water, remaining there about five minutes, rubbing himself well, but 
no soap was used, a sample of the water was then taken. The number of bacteria 
shed from his skin in each instance was calculated. The results varied considerably — 
a dirty male hospital patient shed twenty-five thousand million bacteria, a clean man, 
with a smooth skin, three thousand million, another with a hairy skin fourteen thousand 
million. Now it is obvious that the number of bacteria shed from the skin of a person 
sitting in a slipper bath for about five minutes must be much less than those 
removed from a bather swimming about in a public bath for say a quarter-of-an-hour. 
In the latter case, the friction of the water on the skm is much greater and the 
bacteria removed more numerous. With a view to equalizing the conditions, the 
temperature of the water in the slipper bath was raised to ioo° F., i.e., 30 0 F. above that 
of a swimming bath. 
It is interesting that as the result of five observations made in a first 
class salt water bath in October, 1901, the number of bacteria shed by each bather 
was under three thousand million, instead of four thousand million as obtained in the 
summer. There are two reasons for this curious fact. (1) That as there is less 
moisture on the surface of the skin in cold weather, it affords a less favourable breeding- 
