The Elements of Bacteriological Technique Part 94

8. Remove the animal from the operating table.

9. Label, etc.

~4. Intraperitoneal.~--

(a) _Fluid Inoculum.--(Anaesthetic, none.)_

Steps 1-4. As for cutaneous inoculation. Shave a fairly broad transverse area, stretching from flank to flank.

5. Place the left forefinger on one flank and the thumb on the opposite, and pinch up the entire thickness of the abdominal parietes in a triangular fold. Now, by slipping the peritoneal surfaces (which are in apposition) one over the other, ascertain that no coils of intestine are included in the fold.

6. Take the syringe in the right hand and with the needle transfix the fold near its base (Fig. 182).

7. Now release the fold, but hold the syringe steady; as the parietes flatten out, the point of the needle is left free in the peritoneal cavity (see Fig. 183).

[Ill.u.s.tration: FIG. 182.--Intraperitoneal inoculation--fluid.]

8. Inject the fluid from the syringe.

9. Label, etc.

[Ill.u.s.tration: FIG. 183.--Section of abdominal wall, etc., showing point of needle lying free in the peritoneal cavity above the coils of intestine.]

Second Method:

Steps 1-4. As in the first method.

5. Anaesthetise a small selected area of skin by spraying it with ethyl chloride.

6. Heat platinum searing wire (0.5 mm. wire, twisted to the shape indicated in figure 184, mounted in an aluminium handle) to redness, and with it burn a hole through the anaesthetic area of skin and abdominal muscle down to, but not through, the visceral peritoneum.

7. Fix a blunt-ended needle on to the charged syringe, and by pressing the rounded end firmly against the peritoneum it can easily be pushed through into the peritoneal cavity.

8. Inject the fluid from the syringe.

9. Label, etc.

This method is especially useful when it is desired to collect samples of the peritoneal fluid from time to time during the period of observation, as fluid can be removed from the peritoneal cavity, at intervals, through this aperture in the abdominal parietes, by means of a sterile capillary pipette.

[Ill.u.s.tration: FIG. 184.--Platinum wire for burning hole through parietes.]

(b) _Solid Inoculum_ (or the implantation of capsules containing fluid cultivations).--(_Anaesthetic, A. C. E._)

1. Anaesthetise the animal and secure it to the operating table.

2. Shave a large area of the abdominal parietes.

3. Make an incision through the skin in the middle line about 2 cm. in length, midway between the lower end of the sternum and the p.u.b.es.

4. Divide the aponeuroses between the recti upon a director.

5. Divide the peritoneum upon a director.

6. Introduce the inoculum into the peritoneal cavity.

7. Close the peritoneal cavity with Lembert's sutures.

8. Close the skin and aponeurosis incisions together with interrupted sutures or Michel's steel clips, and apply a sealed dressing.

9. Release the animal from the operating table.

10. Label, etc.

Suitable sacs may be readily prepared by either of the following methods:

A. ~Collodion Sacs.~

1. Dip a small test-tube (5 by 0.5 cm.), bottom downward, into a beaker of collodion, and dry in the air; repeat this process three or four times.

2. Dip the tube, with its coating of collodion, alternately into a beaker of alcohol and one of water. This loosens the collodion and allows it to be peeled off in the shape of a small test-tube.

3. Take a 20 cm. length of gla.s.s tubing, of about the diameter of the test-tube used in forming the sac, and insert one end into the open mouth of the sac.

4. Suspend the gla.s.s tube with attached sac, inside a larger test-tube, by packing cotton-wool in the mouth of the test-tube around the gla.s.s tubing, and place in the incubator at 37 C. for twenty-four hours. When removed from the incubator, the sac will be firmly adherent to the extremity of the gla.s.s tubing.

5. Plug the open end of the gla.s.s tubing with cotton-wool, and sterilise the test-tube and its contents in the hot-air oven.

To use the sac, remove the plug from the gla.s.s tubing, partly fill the sac with cultivation to be inoculated, by means of a sterile capillary pipette, and replug the tubing. When the abdominal cavity has been opened, remove the tubing and attached sac from the protecting test-tube, close the sac by tying a sterilised silk thread tightly around it a little below the end of the gla.s.s tubing, and separate it from the tubing by cutting through the collodion above the ligature, and the sac is ready for insertion in the peritoneal cavity.

B. ~Celloidin Sacs~ (_Harris_).

_Materials Required._

Quill gla.s.s tubing.

Gelatine capsules such as pharmacists prepare for the exhibition of bulky powders.

Various grades of celloidin, thick and thin, in wide-mouthed bottles.

1. Take a piece of quill gla.s.s tubing some 4 cm. long by 5 mm. diameter; heat one end in the bunsen flame.

2. Thrust the heated end of the tube just through one end of a gelatine capsule and allow it to cool (Fig. 185).

3. Remove any gelatine from the lumen of the tube with a heated platinum needle; paint the joint between capsule and tube with moderately thick celloidin and allow to dry.

[Ill.u.s.tration: FIG. 185.--Making celloidin capsules.]

4. Dip the capsule into a beaker containing thin celloidin, beyond the junction with the gla.s.s and after removal rotate it in front of the blowpipe air blast to dry it evenly. Repeat these manoeuvres until a sufficiently thick coating is obtained.