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Table VII.-Number of children included in the study, total possible number of days of

school attendance, and days absent on account of sickness and of causes other than sick-
ness, by months, for the school year 1919-20, in certain localities in Missouri.

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2,059

10,078)

1, 497

All ages:

Both sexes-

Number of children... 6,130 2,701 2,793 2, 856 2,920 3,310 3,608 5,348 5, 194 4,377

Total possible days of

school attendance.... 669,214 54, 020 55, S60 57, 120 58, 400 66,700 72, 160 107,785 110, 269 86, 920

Days absent-Sickness. 37,368 7171 1, 101 2, 422 3,219 4, 226 8,391 7,424 6,430 3, 138

Days absent-Other

causes...

19, 802 1,099 1,402 1,470 1,915 2,094 2,902 3,438' 3,162 2,320

Boys -

Number of children.. 2,870 1,332 1,382 1,413 1,447 1,650 1,779 2,512 2,624 2,115

Total possible days of

school attendance.... 325, 150 26,640 27,640 28, 260 28, 940 33, n0035,590 50,601 52, 633 41, 856

Days absent-Sickness. 17,442 326

646 1, 138 1,396 2,000 4,228 3,333 3,029 1,345

Days absent-Other

causes......

10, 555

583 769 741

1,111 1,575 1,761 1,649 1,294

Girls-

Number of children.. 3,260 1,369 1,411 1,443 1,473 1,690 1,829 2,836 2,870 2,262

Total possible days of

school attendance. 344,064 27,380 28, 220 28, S029, 460 33, 700 36,580 57,161 57,636 45,064

Days absent--Sickness. 19, 926 391 755 1,284 1,823 2,226 4,163 4,091 3, 401 1,792

Days absent-Otl.cr

causes..

9, 247 516 633 726 849) 983 1,327 1,674 1,513 1,026

G to 10 years:

Both seres-

Number of children ... 3, 173 1,421 1,476 1,516 1,542 1,808 1,923 2,801 2,821 2, 229

Total possible days of

school attendance.. 351,313 28, 420 29, 52030, 320 30, 540 36,160 38, 460 56, 244 56, 19644, 853

Days absent-Sickness. 24,413 376 884 1,634

2,724 5,347 4,991 4, 2007 2, 108

Days absent--Otlicr

causes..

023 813 787 1,035 1,180 1,507 1,570 1,409 1,149

Boys-

Number of children.

692

720 743 753 885

946 1,322 1,375 1,091

Total possible days of

school attendance.... 170, 611 13,840 14,400 14,860 15,060 17,700 18,920 26,576 27, 552 21, 703

Days absent-Sickness. 11,352 167 384 737 873 1,305 2,649 2, 299 2,065 883

Days absent-Other

causes...

5,300 303 460 400 567 6381 814 800 706 612

Girls-

Number of children..

1,676 729 756 773 789 923 977 1,479 1,446 1, 138

Total possible days of

school attendance... 180,702 14, 580 15,120 15,460 15,780 18, 460 19,540 29,668 28, 944 23, 150

Days absent-Sickness. 13,061

209 500

897

1,420 2,695 2,692 2, 224 1, 225

Days absent-Other

causes...

4,778 320 353 3.87 468 548) 693 770 702 537

11 to 18 years

Both sexo:

Number of children... 2,957 1,280 1,317 1,349 1,378 1,532 1,685 2, 547 2,673 2,148

Total posible days of

school attendance. 317, 90125, 600 26,340 26,800 27,560 30,540 33, 700 51, 521 53, 773 42,067

Days absent-Sicklers. 12,955 341 517 788 1,160 1,502 3,011 2,433 2,140, 1,030

Davs auscht – Other

Causes...

476 589 683 880 908 1,395 1,868 1,754 1,171

Bogs-

Number of children ... 1,373 640 662 6701 691 765

833 1,190 1,2-19 1,024

Totul possible days of

school attendarie....154, 539 12, 800 13,240 13,400 13, 8N 15,300 16,650 24,025 25, 081 20,153

Days absent--Sickness.

6,090

159

262

401

533 033 1,579 1,034

463

Dars absent - Other

causes....

280 309 344 499 473 761

913 682

Girls-

Number of children ....

640 655 670 684 767 852 1,357 1,424 1,124

Total possible days of

"chool attendance.... 163, 362 12, 890 13,100 13, 400 13,680 15, 240 17,040 27, 19628, 692 21,914

Days absent-Sichuess.

6, 565

182 253 387

S06 1, 465 1,399 1,177 567

Day's absent - Other

causes...

9, 724

9014

196 280 339 381 435 634 901 811 489

4, 469

TABLE VIII.- Number of days lost from school on account of sickness of known cause

and number of cases of known discases among school children 6 to 18 ycars of age, in
certain localities in Missouri during 1919–20.1

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TABLE IX.- Number of days lost from school on account of sickness of known cause
and number of cases of each known disease causing absence among children 6 to 18 years
of age, in certain localities in Missouri during 1919-20.'

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Data given here are for only the small part of the total absence from sickness in which the specific dis-

case was reported.

The following method for determining the phenol coefficient of
disinfectants supersedes the methods described in previous publica-
tions of the Public Health Service and is the present Hygienic Lab-
oratory method.

No single method can serve as a means of comparing the value in
practice of disinfectants of greatly diverse composition and destined
for a variety of applications. However, disinfectants which are chemically related to phenol, which are to be used against organisms reacting similarly to the manner in which the typhoid bacillus reacts and which are destructive within the time and temperature limits of this test, may be compared as to their disinfecting properties within these limitations by means of this test. The results may be useful in the selection of a potent product, in making comparisons of cost in terms of service rendered, and in checking successive batches of the same product.

This method was submitted to several different laboratories for trial before its adoption, and the results seem to justify the belief that the personal equation in the performance of the tests does not play an inordinate rôle.

THE TEST CULTURE.

The test culture is a culture of Bacillus typhosus, Hopkins strain. Between periods of testing it is maintained on nutrient agar stabs, transferred at monthly intervals.

For at least 5 days before the test the culture is transferred at 24-hour intervals to successive tubes of the meat extract broth described below and incubated at 37° C. Transfers are made with one standard loopful. The culture is filtered through sterile filter paper just before using. The test is performed with a 24-hour culture.

THE PHENOL.

The phenol must comply with the requirements of the Eighth United States Pharmacopoeia. Particularly the congealing point must not be below 40° C. The crystals are kept in tightly stoppered amber-colored bottles in a dark and relatively cool place.

A 5 per cent original solution is made by adding 1 part by weight of phenol, liquefied by warming the bottle, to 19 parts of distilled water. A fresh solution is made for each day's use.

THE CULTURE MEDIUM.

3 gm. 10 gm. 5 gm.

Make meat extract medium as follows:

Beef extract (Liebig's)
Peptone (Armour's for disinfectant testing) -
Sodium chloride.
Water, distilled.

1,000 c. c.
Boil for 15 minutes.
Make up to original weight by addition of water.
Filter through paper.
Tube, 10 c. c. to cach tube.
Sterilize.
The pu value of this medium should be between 6.0 and

7.0.

GLASSWARE AND APPARATUS,

Glassware for measuring must be accurately graduated. It must be clean, dry, and sterile at the time of use. There will be needed

1 c. c. capacity pipettes. 5 c. c. capacity pipettes. 1 c. c. delivery pipettes, graduated in tenths. 5 c. c. delivery pipettes. 100 c. c. measuring cylinders, graduated in 1 c. C., glass stoppered. Seeding tubes, 1 x 3 inches, flared tops, round bottoms.

Racks consisting of blocks of wood with rows of holes for both the seeding tubes (before they are placed in the water bath) and the subculture tubes.

Wire loops must be carefully made and kept from damage. They are made as follows: A close cylindrical spiral is made by winding a piece of platinum wire, No. 23, B. & S. gauge, as tightly as possible about a piece of steel or other hard wire having a diameter of 0.072 inch (No. 13, B. & S. gauge) to complete a little more than four full turns. The long end of the wire is then bent sharply at right angles to the wound portion and parallel to the steel wire. The core is removed and the short end of the wire is clipped off so as to leave exactly four full turns to the coil. The successive turns of the spiral must touch one another continuously. The long end of the wire is attached to an aluminum handle.

A convenient support is provided on which to rest the loops so that a batwing Bunsen burner may be placed under each one successively.

A constant temperature bath is provided, capable of maintaining the seeding tubes at 20° C. during the time of the test. A wellinsulated bath of large volume relative to the surface exposed is sufficient without thermoregulating appliances.

Disinfectant testing machine.---The use of a disinfectant testing machine is optional. One is described in Reprint No. 462 from the Public Health Reports. A few modifications have proved useful. For example, the use of platinum instead of nichrome loops, and the practice of sterilizing the subculture tubes covered with padded inverted troughs in the racks.

DILUTIONS.

Dilutions of phenol and of disinfectants are made from the original liquid on the day of the test. For the dilutions of the disinfectant, a 5 per cent solution is made by adding 5 c. c. of the disinfectant to 95 c. c. of sterile distilled water. A standardized 5 c. c. capacity pipette is used for this purpose. After filling the pipette, all excess of the disinfectant on the outside of the pipette is wiped off with

sterile gauze.

The contents of the pipette are then delivered into a cylinder containing 95 c. c. of sterile distilled water and the pipette is washed out as clean as possible by aspiration and blowing out the contents into the cylinder. The contents of the cylinder are then thoroughly shaken and the dilutions up to 1:500 are made from it, using delivery pipettes for measuring. For those disinfectants which do not readily form a 5 per cent solution, make a 1 per cent solution, and from this make the dilutions greater than 1:100 in accordance with the second table of dilutions. If greater dilutions than 1:500 are to be made, a 1 per cent solution is made from the 5 per cent solution and the higher dilutions are made from this.

For the higher dilutions, delivery pipettes may be used. The following scale is used for making dilutions: For dilutions up to 1:70, increase or decrease by a difference of 5

(i.e., 5 parts of water); from 1:70 to 1:160, by a difference of 10; from 1:160 to 1:200, by a difference of 20; from 1:200 to 1:400, by a difference of 25; from 1:400 to 1:900, by a difference of 50; from 1:900 to 1:1800, by a difference of 100; from 1:1800 to 1:3200, by a difference of 200; and so on if higher dilutions are

necessary. It is important that the cylinders used for making the dilutions be correctly graduated. It is preferable to use standardized cylinders and pipettes. For making the dilutions in accordance with the above scheme, the following tables are of service:

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+ + + +

1:20 1:25 1:30 1:35 1:10 1:45 1:50 1:53 1:60 1:65 1:70

or 2

+

20 +

0 or 10 + 0 or 4 20 + 5 or 10 + 2 or 4 20 +

10 or 10 + 5 or 4 20 + 15 or 10 + 74 or 4 20 +

20 or 10 + 10 or 4
20+

25 or 10 + 12 or 4
20 +
30 or

10 + 13 or 4
21) + 35 or 10 + 17) or 4
20 + 40 or 10 + 20 or 4
20 + 45 or 10 + 22 or 4
20 + 50 or 10 + 25

+ +

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20 + 129 or 10 + 60
20 + 139 or 10 + 65
20 + 110 or 10 + 70
20 + 15) or 10 + 75
20 + 160 or 10 + 80
20 + 180 or 10 + 90
20 + 180 or 4 + 35
20 + 20.3 or 4 + 41
20 +231 or 4 + 46
20 + 235 or 4 t 51
20 +280) or 4 + 56
20 + 395 or 4 + 61
20 + 33 ) or 4 + 65
20 + 355 or 4 + 71
2) + 35) or 4 + 76
20) + 13) or 4 85
20 + 480 or 4 + 90

or 4 + 24
or 4 + 26
or 4 +
or 4 +
or 4 + 32
or 4 + 36

+ 18
or 2 + 20
or 2 + 23
or 2 + 251
or 2 + 28
or 2
or 2
or 2
or 2
or 2 +
or 2 +

or 4 20 + 50 or 10 + 2 or 4 20 + 60 or 10 + 30 or 4 20 + 70 or 10 + 35 or 4 20+ $0 or 10 + 40 or 4 20 90 or 10 + 15 or 4 20 + 100 or 10 - 30 or 1 20 + 110 or 10 7. 53 or 4

+ + +

1:70 1:50 1:90 1:100) 1:110 1:1:20 1:130

+ + +

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