The Elements of Bacteriological Technique Part 105

37. Cremate the cadaver together with the board upon which it is fixed.

38. Stain the cover-slip preparations by suitable methods and examine microscopically.

39. Incubate the cultivations and examine carefully from day to day.

40. Make full notes of the condition of the various body cavities and of the viscera immediately the autopsy is completed; and add the result of the microscopical and cultural investigation when available.

As part of the card index system in use in the author's laboratory already referred to (_vide_ page 335) there is a special yellow card for P-M notes. On the face of the card are printed headings for various data--some of which are sometimes unintentionally omitted--and on the reverse is a schematic figure which can be utilised for indicating the position of the chief lesions in the cadaver of any of the laboratory animals.

AUTOPSY CARD Laboratory No. _________

Date ________

Animal ______ No. in Series ______ [Symbols: male female] Weight ________ +------------------------------------------------------------------------+ Died (or killed) _____ o'clock ____ m. Autopsy made _____ o'clock ____ m.

+------------------------------------------------------------------------+ Notes on Post Mortem Examinations.

_General._

A. Seat of Inoculation.

B. Thoracic Cavity.

C. Abdominal Cavity.

D. Cranial Cavity.

+-------------------+---- -------------+--------------------------+ _Bacteriological_ | _Histological_ | _Organs Preserved._ | _Examination._ | _Examination._ | | A. | | | | | | B. | | | | | | C. | | | | | | D. | | |

[Ill.u.s.tration: FIG. 200.--Front of post-mortem card.]

41. Finally, the results of the action of the organism or organisms isolated may be correlated with the symptoms observed during life and the observations summarised under the following headings:

Tissue changes:

1. Local--i. e., produced in the neighbourhood of the bacteria.

Position: (a) At primary lesion.

(b) At secondary foci.

Character: (a) Vascular changes and tissue } Acute reactions. } or (b) Degeneration and necrosis. } chronic.

2. General (i. e., produced at a distance from the bacteria, by absorption of toxins):

(a) In special tissues--e. g., nerve cells and fibres, secreting cells, vessel walls, etc.

(b) General effects of malnutrition, etc.

Symptoms:

(a) a.s.sociated with known tissue changes.

(b) Without known tissue changes.

[Ill.u.s.tration: FIG. 201.--Back of post-mortem card.]

~Permanent Preparations--Museum Specimens.~--

_I. Tissues._--The naked-eye appearances of morbid tissues may be preserved by the following method:

1. Remove the tissue or organ from the cadaver as soon after death as possible, using great care to avoid distortion or injury.

2. Place it in a wide-mouthed stoppered jar, large enough to hold it conveniently, resting on a pad of cotton-wool, and arrange it in the position it is intended to occupy (but if it is intended to show a section of the tissue or organ, do not incise it yet).

3. Cover with the Kaiserling fixing solution, and stopper the jar; allow the tissues to remain in this solution for from forty-eight hours to seven days (according to size) to fix. Make any necessary sections.

Kaiserling modified solution is prepared as follows:

Weigh out

Pota.s.sium acetate 30 grammes.

Pota.s.sium nitrate 15 grammes.

and dissolve in

Distilled water 1000 c.c.

then add

Formalin 150 c.c.

Filter.

This fixing solution can be used repeatedly so long as it remains clear.

Even when it has become turbid, if simple filtration is sufficient to render it clear, the filtrate may be used again.

4. Transfer the tissue to a bath of methylated spirit (95 per cent.) for thirty minutes to one hour.

5. Remove to a fresh bath of spirit and watch carefully. When the natural colours show in their original tints, average time three to six hours, remove the tissues from the spirit bath, dry off the spirit from the cut surfaces by mopping with a soft cloth, then transfer to the mounting solution.

Jore's mounting solution (modified) consists of

Glycerine 500 c.c.

Distilled water 750 c.c.

Formalin 2 c.c.

Equally good but much cheaper is Frost's mounting solution: