1887.] MICROSCOPICAL JOURNAL. 147 
be apparent in some members of a large colony and invisible in others of the 
same group. 
Lagenophrys obovata, sp. nov. (Fig. 14.) 
Lorica obovate, somewhat gibbous, about twice as long as broad, widest 
centrally, tapering posteriorly, the anterior extremity truncate or slightly 
concave ; aperture valvular, the two lips separating and closing at the exten- 
sion and retraction of the ensheathed animalcule. Length of lorica ,4, inch. 
Hab.—Pond water; attached to Canthocamptus minutas. 
In form and size this most nearly resembles Lagenophrys vaginticola, 
Stein, but differs from it in the less cordate aspect of the lorica and in the 
narrower anterior region, the subcentral portion being the widest part of the 
sheath. The lorica becomes chestnut brown with age. 
Fi 
The biological examination of water.—l. 
By ROMYN HITCHCOCK, 
OSAKA, JAPAN. 
The importance of what is now very often designated as the biological ex- 
amination of water is conceded by all microscopists, but comparatively few 
of them are prepared to undertake the work. Many are deterred by the 
array of apparatus that is described in recent books treating of bacteria and 
the methods of cultivating them. Not long ago the writer was called upon 
to make some examinations to determine the number of germs in water. 
Probably there is not a laboratory in Japan fitted up for such work, and it 
would be months before the approved forms of apparatus could be imported. 
It was, therefore, necessary to adapt to the purpose such articles as could be 
found ; and one object of this article is to suggest expedients to those who 
desire to conduct such observations without spending money on costly appa- 
ratus. 
Before proceeding with a description of the apparatus and methods, a few 
words may be said relative to the purposes and practical benefits of such 
investigations. To what extent, for example, are the results trustworthy ? 
Is it possible to say that a given specimen of water is dangerous to health 
because it contains a microbe of a specific disease—typhoid fever or cholera, 
for example? The answer is, that it is not necessary to identify the specific 
microbes of a disease, although it is quite possible to do so ; but whena water 
is found to contain a large number of bacterial spores or living forms it is 
certainly not safe for household use. The mere fact that it contains an abun- 
dance of life shows that it may readily become a carrier of pathogenic forms. 
The importance of micro-organisms in the purification of water is not to 
be disregarded. It is by no means true that a water is dangerous to health 
because it shows many centres of growth on a gelatin plate. Many centres 
of growth do, indeed, indicate the presence in the water of matters which 
sustain an abundance of microscopic life, and it is the function of the organ- 
isms to destroy that organic matter and thus to purify the water. At the 
same time, as already stated, such water may at any time become a carrier 
of pathogenic germs, and it is presumable that such germs might multiply 
very rapidly in a water that is so rich in nutriment for other forms. 
The distinction between the innocuous and the dangerous bacteria can only 
be made by carefully conducted experiments with pure cultures. However, 
it is generally assumed that the forms that liquefy gelatin are derived from 
decomposing animal matter, and they point to contamination of a very ob- 
jectionable kind. : 
As regards the purifying effect of these organisms, F. Emich* has shown 
* Biederm. Centr. Bl. fiir Agr. Chemie xiv, pt. 5. 
