ial observations~ comprise some or all of the following, according
to the method of inoculation and the character of the virus.

1. _The site of inoculation_ should be minutely examined at least at
weekly intervals, and the neighbouring lymphatic glands palpated.

2. Any _local reaction_ at the site of inoculation and any other readily
accessible lesion should be carefully investigated. Any suppurative
process which may occur, whether in the subcutaneous tissues or in
joints, should be explored and the pus carefully examined both
microscopically and culturally.

Fluid secretions and excretions, such as pus or serous exudates when
accessible are collected direct from the body in sterile capillary
pipettes (_vide_ Fig. 13a,) in the following manner:

1. Open the case containing the pipettes, grasp one by the plugged end,
remove it from the case, and replace the lid of the latter.

2. Attach a rubber teat (_vide_ page 10) to the plugged end of the
pipette and use the teat as the handle of the pipette.

3. Pass the entire length of the pipette twice or thrice through the
flame of the Bunsen burner.

4. Snap off the sealed end of the pipette with a pair of sterile
forceps.

5. Compress the india-rubber teat, thrust the point of the pipette into
the secretion; now relax the pressure on the teat and allow the pipette
to fill.

6. Remove the point of the pipette from the secretion, allow the fluid
to run a short distance up the capillary stem and seal the point of the
pipette in the flame. (If using a pipette with a constriction below the
plugged mouthpiece (Fig 13b), this portion of the pipette may also be
sealed in the flame.)

When ready to examine the morbid material snap off the sealed end of the
pipette with sterile forceps and eject the contents of the pipette into
a sterile capsule. The material can now be utilized for cover-slip
preparations, cultivations and inoculation experiment.

3. _The peripheral blood_ should be examined from time to time for from
this tissue is often obtained the fullest information as to the course
and progress of an infection.

a. The ~histological examination of the blood~ should be directed
chiefly to observations on the number and kind of white cells; and since
but few bacteriologists are at the same time expert comparative
haematologists, some notes on the normal characters of the blood of the
commoner laboratory animals, contrasted with those of man, are inserted
for refer