Annual report of the Directory of Lands. [1904]

156 REPORT OF THE PHILIPPINE COMMISSION.
"Recent unpublished work in this laboratory by Mr. Clegg and myself has shown
that within certain limits amoebas are adaptable, and that this varying degree of
pathogenicity is influenced by the environment of the organism. It is apparently
increased by passage through the animal organism, and it is likely also to be
influenced by the class of bacteria and other substances with which it may be associated. This work has progressed far enough to indicate that the further and longer
removed from animal organic matter and possibly from some bacteria quite common
in man the less likely will the amoebas be pathogenic to human beings on direct
inoculation. This statement is offered as an additional reason for a complete removal
of animal life from the proposed new watershed.
"The amcebas isolated from and above the proposed new reservoir will be studied
more in detail and an additional report subnitted if it is so desired.
"In closing I wish to emphasize that provisions for a safe water supply for Manila
must include methods for removal of animal parasites which are present in the
Mariquina River and its tributaries."
The table of the chemical examination, which is inclosed, shows the composition
of the water.
The results given above would indicate that in the future investigations the following course should be adopted. A model cross section of the filter which it is proposed to use should be made in a glass tube of sufficient diameter, which can be furnished by the laboratories, and tap water will then be run through the filter for a
long time. The water taken from the lower end will then be examined immediately
after installation, and at intervals afterwards, in order to determine whether the
amombas will finally force passage through or not. This will experimentally determine the efficiency of the filters and also whether they can be kept in use for any
considerable length of time and how often cleaning must take place.
It is also suggested that the laboratories make a second expedition to the source
of the water supply at the beginning of the rainy season for the purpose of determining what influence the rains will have upon the condition of the water supply. It
is requested that the city engineer cooperate with the laboratories in preparing a
model of the filter to be used, and also when the rains begin assist in sending a
second expedition to the source of the supply. The laboratories will send a botanist
above Montalbon as soon as possible to study the vegetation in the river.
I am, very respectfully,
PAUL C. FREER,
Supeeri-ltendent Gorerzmtenut Laboraturics.
DEPARTMENT OF ENGINEERING AND PUBLIC WORKS,
OFFICE OF CITY ENGINEER,
Mfanila, April 23, 1904.
The SECRETARY MUNICIPAL BOARD, Manila, P. I.
SIR: Mr. Desmond FitzGerald, consulting engineer, has kindly furnished me with
an advance copy of his report of the plans of the proposed water system for the city
of Manila, and I desire to present the following observations, which may be considered supplementary to my original formal report:
In the first place, I desire to express my pleasure at the opportunity of being associated with Mr. FitzGerald in this work. The thoroughness of his investigations and
the value of his advice in the discussions we have had, as well as his unfailing courtesy,
have made our relations most pleasant and profitable to me. It is especially gratifying also to have his distinct and complete approval of my plans.
Taking Mr.- FitzGerald's report by paragraph, it will be noticed that we agree as
to the quantity of water to be supplied under the head of "Future requirements."
The "Source of supply" selected by me meets Mr. FitzGerald's entire approval.
The "Watershed" and "Proposed forest reserve " are agreed to. Mr. FitzGerald's
notes on "Rainfall and storage" agree very closely to my own. Mr. FitzGerald
assumes somewhat more rigid conditions than I did, which may be best described
by stating that my computations were based on the assumption that the three driest
seasons during the observed period might occur consecutively, while Mr. FitzGerald's
more rigid assumption is that the driest year of the entire observed period might
occur for three consecutive years. Mr. FitzGerald's storage results are therefore
somewhat in excess of my own, though I wish to call attention to the fact that the
" Storage reservoir" as designed by me is still of ample capacity should Mr. FitzGerald's assumption become an actual fact.
It will be noticed that the design of the dam at the gorge is approved both as to
location and section. As Mr. FitzGerald states, all that man can do will have been