266 The Philippine Journal of Science 1921 
At the same time, it is possible that a single worm might, by 
setting up an inflammatory process, lead to the blockage of a 
main lymphatic trunk, in which event embryos would be absent, 
and yet the case might present some of the characters of filarial 
disease. It is quite possible also that such a worm in its death 
might give rise to filarial abscess. 
In this connection one may perhaps refer again to the ten- 
dency of the worms to pass in pairs into the proboscis of the 
mosquito; it may be intended by nature thus to provide, by the 
introduction of a male and a female, for reproduction. 
The whole subject is one that needs careful working out, in 
view of its importance in devising prophylactic measures. For 
the present no doubt the mosquito net is the reasonable means of 
prophylaxis, each infected individual being a source of danger 
to the community. 
MICROSCOPICAL DIAGNOSIS 
For examination of fresh specimens, it is only necessary to take 
a large drop of the patient’s blood, cover it gently with a 
cover glass, and examine it under a low power of the micro- 
scope, when the filaria is easily distinguished by its movement. 
If such preparations are ringed with vaseline, it is possible 
to preserve them for some time: at any rate, the filariz may 
be kept alive for at least a week. 
For systematic study it is better to keep to a fixed time. In 
these researches for statistical purposes all the specimens were 
taken between 9.30 and 10 o’clock in the evening. As my pa- 
tients used to go to sleep at an early hour, and were up at 
daylight, this time was late enough. 
For this class of work it is better to use specimens prepared 
in the following way: The blood is taken from the finger or 
ear, a lancet or triangular needle being the best instrument for 
the purpose. Several drops of blood should be received on a 
glass slip and spread out gently with the needle. The slide 
must then be laid aside on a flat surface and covered, to prevent 
dust spoiling the specimen. Two specimens at least should be 
taken from each patient. As soon as convenient, and the sooner 
the better, these slides, which must be already dry, are fixed 
by warming them over a spirit flame, and then are immersed 
in water. This dissolves out the hemoglobin and leaves a 
colorless specimen, which is then placed in a watery solution 
of methylene blue for a few minutes, passed through water, 
and examined wet without a cover glass under a 1-inch ob- 
jective. The filarie are easily distinguished, being stained a 
