A disinfectant is an agent that has the power to destroy microbic life, i. e., it is a germicide. An antiseptic is an agent that tends to retard the growth of microorganisms.

A deodorant or deodorizer is an agent that will destroy or overcome a foul odor. It may or may not be disinfectant. Examples of such are: (1) For general use, chlorinated lime, cologne water, charcoal, the smoke of burning paper, burning straw, or burning coffee; (2) for bad breath, antiseptic solution, N. F. (containing boric acid, thymol, eucalyptol, methyl salicylate, oil of thyme, sodium salicylate, sodium benzoate, alcohol, and water), or hydrogen dioxide; (3) for fetid breath, creosote; (4) in foul ulcers, potassium permanganate, hydrogen dioxide, or formal-dehyd.

A preservative is an antiseptic agent used to prevent microbic changes (fermentation, putrefaction) in organic material, such as food, medicines, etc. Preservatives are so extensively employed in butter, milk, soups, vegetables, meat, etc., that it is possible to ingest a large quantity of one preservative or small doses of each of several preservatives at a single meal. Many of them retard decomposition without checking the activity of pathogenic germs.

Sterilization is any process by which a substance is made germ-free. It usually implies destruction of germs by heat at 100° C. (212o F.) or higher. Pasteurization is a form of partial sterilization at 160o F. for half an hour. It is used for milk.

The ideal antiseptic or disinfectant for use about the body is one with a maximum action on microorganisms and a minimum action on the body tissues. Of blood disinfectants, quinine in malaria and salvarsan in syphilis would seem most nearly to approach this ideal; though their destructive effect is limited to certain organisms only.

The germicidal value of many disinfectants is seriously interfered with by organic matter, especially blood-serum, so that the germicide that is strongest in the test-tube may be the weakest when in contact with the body tissues. Moreover, many germicides are decidedly more destructive to human tissues than to germs, so that their use may result in a lowering of the local resistance of the patient. (See Lambert's report on Iodine, page 499.)

Tests With Albuminous Fluids

On mixing hydrocele fluid with an equal quantity of an antiseptic solution of sodium aurate, argyrol, and protargol (Verhoeff, 1906), and of collargol, albargin, ichthargan, argentamine, largin, and argonin (Derby, 1909), the germicidal effects were inhibited. With the same method, Verhoeff and Ellis (1907) found that lysol, 1 per cent., creolin, 1 per cent., listerine, 100 per cent., and liquor antisepticus, N. F., 100 per cent., failed to kill Staphylococcus aureus in two hours. The last-named authors also demonstrated that neither acetozone 1: 1000, alphozone 1: 1000, nor zinc sulphocarbolate, 1 per cent., mixed with solution of albumin, was successful in sterilizing typhoid culture in twenty-four hours; and that, mixed with albumin, alkalol, 100 per cent., borol, 50 per cent., alkathy-mol, 100 per cent., glycothymoline, 100 per cent., zinc sulphocarbolate, 1 per cent., and cuprol, 5 per cent., each failed to destroy Staphylococcus aureus in four hours. (See also under Silver.)

Post and Nicoll (1910) made extensive tests, and reported the number of colonies in a loopful of test solution after different lengths of time.

From their work the following table is compiled:

Solution

Streptococcus

Gono-coccus

Pneumo-coccus

Bacillus Typhosus

After What Time in Minutes

1.

Silver preparations:

Argyrol, 50 per cent............

3,000

0

One.

0

2,000

200

0

Thirty.

Argyrol, 10 per cent............

2,000

0

One.

11

0

7

0

Thirty.

Protargol, 10 per cent .........

600

200

<

0 1,000

One.

0

0

0

0

Thirty.

Silver nitrate, 1 per cent.. ..

0

0

0

0

One.

Silver nitrate, 1: 1000 .........

0

0

<

0 20

500

One.

0

0

0

0

Thirty.

Silver nitrate, 1: 5000 ........

<

I II

0 0

50

1,000

One.

0

0

0

0

Thirty.

II.

Mercury preparations:

Mercuric bichloride, 1 : 500

2,000

3,000

3,000

0

One.

0

1

0

0

Thirty.

Mercuric biniodide, 1 : 1000

10

0

0

One.

0

0

4,000

0

Thirty.

III.

Phenols:

Phenol, 5 per cent.........

0

0

0

0

One.

Phenol, 1 per cent ................

4,000

8,000

6,000

One.

500

0

4,000

1,000

Thirty.

Trikresol, 1 per cent...............

0

0

0

0

One.

Trikresol, 0.3 per cent...........

4,000

2,000

10,000

2,000

One.

Lysol, 1.5 per cent................

0

0

400

10,000

One.

0

0

0

0

Thirty.

500

6,000

One.

Lysol, 1: 1000 .......................

12

1,000

4,000

Thirty.

0

25

300

1

One.

Creolin, 1 per cent .................

0

0

0

0

Thirty.

IV.

Iodine preparations:

Tincture (7 per cent.) ..........

0

0

0

0

One.

Iodine .......................1

0

0

0

0

One.

Potassium iodide ......1

Water... to make 100

V.

Formaldehyde preparations:

Liquor formaldehydi, U.S.P.

0

0

0

0

One.

Liquor formaldehydi, 1 per cent .................

10,000

4,000

5,000

One.

500

1,000

200

50

Thirty.

Solution

Stkepto-coccus

Gono-coccus

Pneumo-coccus

Bacillus Typhosus

After What Time in Minutes

VI. Alcohol:

20 per cent.........................................

300

300

8,000

4,000

One.

3

0

8,000

2,000

Thirty.

30 per cent .......................................

25

0

2,000

300

One.

50 per cent ....................................

0

0

0

0

One.

70 per cent .....................................

0

0

0

0

One.

VII. Miscellaneous:

Tincture of green soap .......................

0

0

0

0

One.

Hydrogen dioxide..............................

200

1,000

2,000

0

One.

0

0

0

0

Thirty.

Thiersch's solution ..............................

0

0

5,000

<

10,000 0

One.

0

0

0

0

Thirty.

Potassium permanganate,

1: 1000 .........................................

3,000

2,000

One.

0

0

2,000

0

Thirty.

Copper sulphate, 1 per cent.

4,000

6,000

3,000

One.

5,000

2,000

4,000

1,000

Thirty.

Boric acid, saturated (1 : 18)

3,000

10,000

One.

2,000

2,000

5,000

Thirty.

Potassium chlorate, saturated, 6.6 per cent...........................

3,000

10,000

One.

5,000

2,000

5,000

Thirty.

Glycerin ...........................................

2,000

6,000

One.

1,000

4,000

Thirty.

Distilled water ..................................

10,000

4,000

10,000

One.

These results establish: (1) The reliability and prompt action of a few simple germicides, such as tincture of green soap, alcohol in solutions above 50 per cent., silver nitrate as dilute as 1:1000, the iodine solutions, and 5 per cent. phenol. (2) The unreliability of many agents prevalently supposed to be effective germicides. (3) The slow action of mercuric chloride, though when given hours to act it is effective in high dilutions.

Classification, according to the nature of the agent:

1. Heat and cold.

2. Oxidizers.

3. Deoxidizers.

4. Free halogens and their compounds.

5. Metals and metallic salts.

6. Miscellaneous inorganic compounds.

7. Phenol and its allies.

8. Miscellaneous organic compounds.