----------------------------+-----------+----------+---------+---------- | | | | Fuel Food materials. | Weight. | Cost. | Protein.| Value.
----------------------------+-----------+----------+---------+---------- | | | | _Breakfast._ |Lbs. Oz. | Cents. | Pounds. | Calories.
| | | | Oatmeal | 0 2 | | / .019 | 232 Milk | 6-1/2 | > 2 |< .012="" |="" 122="" sugar="" |="" 1="" |/="" |="" ...="" |="" 175="" fresh="" pork="" sausage="" |="" 1="" 8="" |="" 18="" |="" .192="" |="" 3,255="" potatoes="" |="" 12="" |="" 1="" |="" .013="" |="" 244="" bread="" |="" 12="" |="" 3="" |="" .071="" |="" 904="" b.u.t.ter="" |="" 2="" |="" 4="" |="" ...="" |="" 434="" coffee="" |="" ...="" |="" 3-1/2="" |="" .010="" |="" 410="" |-----------+----------+---------+----------="" total="" |="" |="" 31-1/2="" |="" .317="" |="" 5,776="" |="" |="" |="" |="" _dinner._="" |="" |="" |="" |="" |="" |="" |="" |="" beef,="" for="" stew="" |="" 2="" 8="" |="" 15="" |="" .347="" |="" 1,900="" potatoes="" |="" 1="" 8="" |="" 2="" |="" .027="" |="" 487="" turnips="" |="" 8="" |="" 1="" |="" .005="" |="" 67="" bread="" |="" 8="" |="" 2="" |="" .048="" |="" 603="" b.u.t.ter="" |="" 1="" |="" 2="" |="" ...="" |="" 217="" indian="" pudding:="" |="" |="" |="" |="" cornmeal="" |="" 4="" |="" |="" .022="" |="" 414="" mola.s.ses="" |="" 4="" |="" 6="" |/="" .007="" |="" 329="" b.u.t.ter="" |="" 1/2="" |="" |="" ...="" |="" 108="" skim="" milk="" |="" 2="" 0="" |/="" |="" .068="" |="" 340="" coffee="" |="" ...="" |="" 3-1/2="" |="" .010="" |="" 410="" |-----------+----------+---------+----------="" total="" |="" |="" 31-1/2="" |="" .534="" |="" 4,875="" |="" |="" |="" |="" _supper._="" |="" |="" |="" |="" |="" |="" |="" |="" corned="" beef="" hash:="" |="" |="" |="" |="" corned="" beef,="" canned="" |="" 8="" |="" 6="" |="" .142="" |="" 560="" potatoes="" |="" 8="" |="" 1="" |="" .009="" |="" 162="" bread="" |="" 12="" |="" 3="" |="" .071="" |="" 904="" b.u.t.ter="" |="" 2="" |="" 4="" |="" ...="" |="" 434="" apples="" |="" 12="" |="" 1="" |="" .003="" |="" 191="" milk="" |="" 2="" 0="" |="" 6="" |="" .066="" |="" 725="" |-----------+----------+---------+----------="" total="" |="" |="" 21="" |="" .291="" |="" 2,976="" |="==========|==========|=========|==========" total="" per="" day="" |="" |="" 84="" |="" 1.142="" |="" 13,627="" |="==========|==========|=========|==========" total="" for="" one="" man="" |="" |="" 21="" |="" .285="" |="" 3,407="" ----------------------------+-----------+----------+---------+----------="">
In these menus the amount of milk has, as a rule, been taken as representing somewhere near the average consumption. The amount of milk can be increased in any of the menus given above either by subst.i.tuting it to some extent for coffee or tea, or by using more milk and smaller quant.i.ties of meats, b.u.t.ter or eggs. Roughly speaking, 1 quart of whole milk could be subst.i.tuted for half a pound of meat or eggs and the amount of nutrients would be the same, while a pint of milk would give as large a fuel value as 1-1/2 ounces of b.u.t.ter, and in addition considerable protein not furnished by the latter.
This replacement of meats by milk is ill.u.s.trated in the following menu, in which a diet with a rather small quant.i.ty of milk is so changed as to include a much larger amount. Thus for breakfast in the modified ration a pint and a half of milk is made to take the place of half a pound of broiled steak. For dinner a quart of skim milk (or b.u.t.termilk) is called for, or a gla.s.s for each person unless some of it is used in the cooking. At the same time, 4 ounces less roast pork is required. In the same way a gla.s.s of whole milk is allowed each person for supper, or the bread can be made into milk toast and the most of the extra milk used in this way. This allows the canned salmon to be reduced 6 ounces.
MENU III.--_For family equivalent to 4 men at moderate exercise._
--------------------------+---------------------------------- | Weight of food.
|-----------------+---------------- Food materials. | With | With | small | large | amount | amount | of milk. | of milk.
--------------------------+-----------------+---------------- | | _Breakfast._ | Lbs. Oz. | Lbs. Oz.
| | Bananas, apples, or pears | 0 12 | 0 12 Wheat preparation | 4 | 4 Milk | 8 | 8 Sugar | 2 | 2 Broiled sirloin steak | 1 4 | 12 Baked potatoes | 1 8 | 1 8 Hot rolls | 1 0 | 1 0 b.u.t.ter | 2-1/2 | 2-1/2 Extra milk | | 1 8 | | _Dinner._ | | | | Tomato soup | 1 12 | 1 12 Roast pork | 1 12 | 1 8 Mashed potatoes | 1 4 | 1 4 Turnips | 8 | 8 Apple fritters: | | Apples | 8 | 8 Flour | 2 | 2 1 egg | 2 | 2 Lard | 1-1/2 | 1-1/2 Bread | 8 | 8 b.u.t.ter | 2 | 2 Extra skim milk | | 2 0 | | _Supper._ | | | | Canned salmon | 1 6 | 1 0 Potatoes | 12 | 12 Bread | 8 | 8 b.u.t.ter | 2 | 2 Berries, canned or fresh | 8 | 8 Extra milk | | 2 0 --------------------------+-----------------+-----------------
_Cost, protein, and fuel value of the above._
-----------------------------+-------------+--------------+------------ | Cost. | Protein. | Fuel | | | Value.
-----------------------------+-------------+--------------+------------ | | | _With small amount of milk._ | Cents. | Pounds. | Calories.
| | | | | | Breakfast | 48 | .39 | 5,300 Dinner | 51 | .39 | 5,800 Supper or lunch | 33-1/2 | .34 | 3,200 |-------------+--------------+------------ Total per day | 132-1/2 | 1.12 | 14,300 |=============|==============|============ Total for one man | 33 | .28 | 3,575 |=============|==============|============ | | | _With large amount of milk._ | | | | | | Breakfast | 43 | .36 | 5,270 Dinner | 47-1/2 | .41 | 5,400 Supper or lunch | 34-1/2 | .34 | 3,600 |-------------|--------------|------------ Total per day | 125 | 1.11 | 14,270 |=============|==============|============ Total for one man | 31 | .28 | 3,567 -----------------------------+-------------+--------------+------------
Menus VI and VII, following, are intended to ill.u.s.trate how nourishing food can be procured in sufficient quant.i.ties and moderate variety at a cost of not over 16 cents per day. The cost to the farmer would be much less, since these menus call for considerable amounts of milk, which is hardly worth more than one-half or one-third as much on the farm as it costs in the towns and cities. Coffee has not always been indicated, but can be introduced for any meal at a cost of from 1/2 to 1-1/2 cents per cup, according to how much coffee is used in making the infusion, and how much sugar, milk, and cream are added.
It is, of course, not important that each meal, or the total food of each individual day, should have just the right amount of nutrients, or that the proportions of protein and fuel ingredients should be exactly correct so as to make the meal or day"s diet well balanced.
The body is continually storing nutritive materials and using them. It is not dependent any day upon the food eaten that particular day.
Hence an excess one day may be made up by a deficiency the next or _vice versa_. Healthful nourishment requires simply that the nutrients as a whole, during longer or shorter periods, should be fitted to the actual needs of the body for use.
MENU IV.--_For family equivalent to 4 men at moderate muscular work._
----------------------------+-----------+----------+---------+---------- | | | | Fuel Food materials. | Weight. | Cost. | Protein.| Value.
----------------------------+-----------+----------+---------+---------- | | | | _Breakfast._ |Lbs. Oz. | Cents. | Pounds. | Calories.
| | | | Bananas, 4 (or grapes, | | | | 1 pound) | 1 4 | 6-1/2 | .009 | 362 Breakfast cereal | 4 | | / .031 | 421 Milk | 6 | > 3 |< .012="" |="" 122="" sugar="" |="" 2="" |/="" |="" ...="" |="" 232="" mutton="" chops="" |="" 1="" 4="" |="" 20="" |="" .165="" |="" 1,812="" potatoes="" |="" 1="" 0="" |="" 1-1/2="" |="" .018="" |="" 325="" b.u.t.ter="" |="" 3="" |="" 6="" |="" ...="" |="" 653="" rolls="" |="" 12="" |="" 4="" |="" .077="" |="" 1,148="" coffee="" |="" ...="" |="" 3-1/2="" |="" .010="" |="" 410="" |-----------+----------+---------+---------="" total="" |="" |="" 44-1/2="" |="" .322="" |="" 5,485="" |="" |="" |="" |="" _dinner._="" |="" |="" |="" |="" |="" |="" |="" |="" tomato="" soup="" |="" 2="" 0="" |="" 12="" |="" .036="" |="" 370="" roast="" pork="" |="" 2="" 8="" |="" 32="" |="" .353="" |="" 3,350="" potatoes="" |="" 1="" 4="" |="" 1-1/2="" |="" .022="" |="" 406="" turnips="" |="" 8="" |="" 1="" |="" .005="" |="" 67="" |="" |="" |="" |="" tapioca="" pudding:="" |="" |="" |="" |="" tapioca="" |="" 3="" |="" |="" .001="" |="" 310="" apples="" |="" 1="" 0="" |="" |/="" .004="" |="" 255="" sugar="" |="" 2="" |="" 7="" |="" ...="" |="" 232="" cream="" |="" 4="" |/="" |="" .006="" |="" 228="" coffee="" |="" ...="" |="" 3-1/2="" |="" .010="" |="" 410="" |-----------+----------+---------+----------="" total="" |="" |="" 57="" |="" .437="" |="" 5,628="" |="" |="" |="" |="" _supper._="" |="" |="" |="" |="" |="" |="" |="" |="" milk="" toast:="" |="" |="" |="" |="" milk="" |="" 2="" 0="" |="" |="" .066="" |="" 650="" bread="" |="" 1="" 2="" |="" 18="" |/="" .107="" |="" 1,356="" b.u.t.ter="" |="" 4="" |="" |="" ...="" |="" 869="" cornstarch="" |="" 2="" |/="" |="" ...="" |="" 238="" sliced="" cold="" pork="" |="" 8="" |="" 6="" |="" .071="" |="" 670="" fried="" potatoes:="" |="" |="" |="" |="" potatoes="" |="" 8="" |="" 1="" |/="" .009="" |="" 162="" lard="" |="" 1/2="" |/="" |="" ...="" |="" 132="" cake="" |="" 6="" |="" 4="" |="" .026="" |="" 619="" coffee="" or="" tea="" |="" ...="" |="" 3-1/2="" |="" .010="" |="" 410="" |-----------+----------+---------+----------="" total="" |="" |="" 32-1/2="" |="" .289="" |="" 5,096="" |="==========|==========|=========|==========" total="" for="" day="" |="" |="" 134="" |="" 1.048="" |="" 16,209="" |="==========|==========|=========|==========" total="" for="" one="" man="" |="" |="" 33-1/2="" |="" .262="" |="" 4,052="" ----------------------------+-----------+----------+---------+----------="">
MENU V.--_For family equivalent to 4 men at moderate muscular work._
----------------------------+-----------+----------+---------+---------- | | | | Fuel Food materials. | Weight. | Cost. | Protein.| Value.
----------------------------+-----------+----------+---------+---------- | | | | _Breakfast._ |Lbs. Oz. | Cents. | Pounds. | Calories.
| | | | Baked apples | 2 0 | 2 | .008 | 510 Boiled hominy | 8 | | / .041 | 823 Milk | 10 | > 4-1/2 |< .020="" |="" 202="" sugar="" |="" 3="" |/="" |="" ...="" |="" 350="" broiled="" sirloin="" |="" 10="" |="" 11="" |="" .099="" |="" 650="" potatoes="" |="" 8="" |="" 1="" |="" .009="" |="" 162="" m.u.f.fins:="" |="" |="" |="" |="" 1="" egg="" |="" 4="" |="" 5="" |/="" .032="" |="" 162="" 2="" cups="" flour="" |="" 8="" |/="" |="" .057="" |="" 820="" b.u.t.ter="" |="" 2="" |="" 4="" |="" ...="" |="" 435="" coffee="" |="" ...="" |="" 3-1/2="" |="" .010="" |="" 410="" |-----------+----------+---------+----------="" total="" |="" |="" 31="" |="" .276="" |="" 4,524="" |="" |="" |="" |="" _dinner._="" |="" |="" |="" |="" |="" |="" |="" |="" tomato="" soup="" |="" 2="" 0="" |="" 6="" |="" .036="" |="" 370="" veal="" stew,="" shoulder="" |="" 2="" 0="" |="" 20="" |="" .332="" |="" 1,350="" potatoes="" |="" 3="" 0="" |="" 4-1/2="" |="" .054="" |="" 975="" apple="" dumpling:="" |="" |="" |="" |="" 1="" egg="" |="" 2="" |="" |="" .016="" |="" 81="" 4="" apples="" |="" 1="" 8="" |="" 8="" |/="" .006="" |="" 382="" 1/2="" cup="" lard="" |="" 4="" |="" |="" ...="" |="" 1,055="" 1="" cup="" flour="" |="" 4="" |/="" |="" .028="" |="" 410="" |="" |="" |="" |="" sauce="" for="" dumpling:="" |="" |="" |="" |="" b.u.t.ter="" |="" 1="" |="" 3="" |/="" ...="" |="" 217="" sugar="" |="" 4="" |/="" |="" ...="" |="" 465="" bread="" |="" 12="" |="" 3="" |="" .071="" |="" 904="" b.u.t.ter="" |="" 1="" |="" 2="" |="" ...="" |="" 217="" coffee="" or="" tea="" |="" ...="" |="" 3-1/2="" |="" .010="" |="" 410="" |-----------+----------+---------+---------="" total="" |="" |="" 50="" |="" .553="" |="" 6,836="" |="" |="" |="" |="" |="" |="" |="" |="" _supper="" or="" lunch._="" |="" |="" |="" |="" |="" |="" |="" |="" dried="" canned="" corned="" beef="" |="" 8="" |="" 6="" |="" .142="" |="" 560="" potato="" croquette="" |="" 8="" |="" 1="" |="" .009="" |="" 162="" biscuit="" |="" 12="" |="" 4="" |="" .070="" |="" 1,297="" b.u.t.ter="" |="" 1-1/2="" |="" 3="" |="" ...="" |="" 325="" oranges,="" 4="" |="" 1="" 4="" |="" 7="" |="" .007="" |="" 400="" skim="" milk="" |="" 1="" 6="" |="" 2="" |="" .046="" |="" 234="" |-----------+----------+---------+----------="" total="" |="" |="" 23="" |="" .274="" |="" 2,978="" |="==========|==========|=========|==========" total="" for="" day="" |="" |="" 104="" |="" 1.103="" |="" 14,338="" |="==========|==========|=========|==========" total="" for="" one="" man="" |="" |="" 26="" |="" .275="" |="" 3,585="" ----------------------------+-----------+----------+---------+----------="">
MENU VI.--_For family equivalent to 4 Men at moderate muscular work._
----------------------------+-----------+----------+---------+---------- | | | | Fuel Food materials. | Weight. | Cost. | Protein.| Value.
----------------------------+-----------+----------+---------+---------- | | | | _Breakfast._ |Lbs. Oz. | Cents. | Pounds. | Calories.
| | | | Cornmeal, in mush or cake | 0 5 | 1 | .022 | 414 Milk | 6 | 1 | .012 | 64 Sugar | 2 | 1/2 | ... | 232 Toast | 10 | 2-1/2 | .059 | 753 b.u.t.ter (24 cents per pound) | 2 | 3 | ... | 434 |-----------+----------+---------+---------- Total | | 8 | .093 | 1,897 | | | | _Dinner._ | | | | | | | | Beef roll (for roasting) | 3 0 | 15 | .417 | 2,280 Potatoes | 1 8 | 2 | .026 | 488 Beets | 8 | 1 | .007 | 85 Bread | 10 | 2-1/2 | .059 | 753 b.u.t.ter | 2 | 3 | ... | 434 |-----------+----------+---------+---------- Total | | 23-1/2 | .509 | 4,040 | | | | _Supper._ | | | | | | | | Beans, baked | 2 0 | 6 | .446 | 3,180 Pork | 12 | 6 | .012 | 2,556 Potatoes, fried | 1 8 | 2 | .026 | 488 Lard | 2 | 1 | ... | 537 Bread | 10 | 2-1/2 | .059 | 753 b.u.t.ter | 2 | 3 | ... | 434 |-----------+----------+---------+---------- Total | | 20-1/2 | .543 | 7,948 |===========|==========|=========|========== Total for day | | 20-1/2 | 1.145 | 13,885 |===========|==========|=========|========== Total for one man | | 13 | .285 | 3,471 ----------------------------+-----------+----------+---------+----------
MENU VII.--_For family equivalent to 4 men at moderate muscular work._
----------------------------+-----------+----------+---------+---------- | | | | Fuel Food materials. | Weight. | Cost. | Protein.| Value.
----------------------------+-----------+----------+---------+---------- | | | | _Breakfast._ |Lbs. Oz. | Cents. | Pounds. | Calories.
| | | | Oatmeal | 0 6 | 2 | .059 | 697 Skim milk, 1 pint | 1 0 | 1-1/2 | .034 | 170 Sugar | 2 | 1/2 | ... | 232 Bread (homemade) | 1 0 | 3 | .095 | 1,205 Sausage | 10 | 6 | .080 | 1,358 b.u.t.ter (24 cents per pound) | 1 | 1-1/2 | ... | 217 |-----------+----------+---------+---------- Total | | 14-1/2 | .268 | 3,879 | | | | _Dinner._ | | | | | | | | Beef flank, stew | 2 8 | 15 | .430 | 2,988 Potatoes (60 cents per | | | | bushel) | 3 0 | 3 | .054 | 975 Cabbage | 12 | 1 | .013 | 105 Cornmeal pudding: | | | | Cornmeal | 4 | 1/2 | .022 | 414 Skim milk, 1 quart | 2 0 | 3 | .068 | 340 Mola.s.ses | 12 | 1 | .020 | 987 |-----------+----------+---------+---------- Total | | 22-1/2 | .604 | 5,889 | | | | _Supper._ | | | | | | | | Beef, warmed in gravy | 1 8 | 3 | .086 | 598 Hot biscuit | 2 0 | 6 | .340 | 2,600 b.u.t.ter | 2 | 3 | ... | 434 Milk, 1 quart | 2 0 | 6 | .033 | 325 |-----------+----------+---------+---------- Total | | 18 | .259 | 3,957 |===========|==========|=========|========== Total per day | | 55 | 1.134 | 3,645 |===========|==========|=========|========== Total for one man | | 14 | .285 | 3,411 ----------------------------+-----------+----------+---------+----------
DISCUSSION OF THE MENUS.
These menus attempt to give, as nearly as convenient, the range of food materials and the variety of combination which might be found in the average well-to-do household. Some of the menus are more varied and costly than others, and a few are given showing the effect of the use of more milk, and also how a diet might easily become one-sided.
The quant.i.ties of the different foods used per meal will not, it is believed, be found out of proportion to each other, though of course they will not suit every family. The weights of all materials, oatmeal and other cereals, meat, vegetables, etc., are for these substances as purchased.
The calculation of the quant.i.ties of nutrients contained in the different foods is based upon the average percentage composition of these materials. Inasmuch as the fats and carbohydrates are used simply as fuel they are not shown in the menus, only the quant.i.ty of protein and the fuel value of the food being of interest.
The cost of the different food materials must of necessity be more or less of a varying quant.i.ty, depending upon the season of the year, the character of the markets, large or small, city or country, etc. Of the more important food materials the a.s.sumed price per pound is as follows: Beef loin, 18 to 25 cents; shoulder, 12 cents; round, 14 cents; chicken, 15 cents; mutton loin, 16 cents; lamb leg, 20 cents; bacon, 16 cents; sausage, 10 cents; milk, 3 cents (6 cents per quart); skim milk, 1-1/2 cents (3 cents per quart); b.u.t.ter, 32 cents; cheese, 16 cents; eggs, 16 cents (24 cents per dozen); flour and meal, 2-1/2 to 3 cents; cereals, 5 to 8 cents; bread, 4 cents; potatoes and other vegetables, 1-1/2 cent (90 cents per bushel); bananas, about 8 cents (20 cents per dozen); oranges, about 7 cents (25 to 40 cents per dozen); apples, 1-1/2 cent per pound (90 cents per bushel).
It is probable that the above figures represent more nearly the average prices of the different food materials in the eastern part of the country than in the central and western portions, where meats, cereals, and many other products are somewhat cheaper. It is also to be borne in mind that by observing the markets many food materials can be purchased much cheaper than here indicated, while on the other hand there may be times when they will be much more expensive. The choice of vegetables and fruits will naturally be governed by their abundance and cost.
Another point that must not be overlooked is that the quant.i.ties, and consequently the costs, here given are for four working men; that is to say, men engaged in moderately hard muscular labor. Of course, different individuals differ greatly in their needs for food. These figures express only general averages and are based upon the best information accessible.
A FEW POINTS TO BE CONSIDERED IN PLANNING MEALS.
Dietetic authorities advise people who are engaged in active muscular work to partake of the more substantial meal in the middle of the day, leaving such articles of food as soup--which is a valuable stimulant after a day of hard work--fruit, cake, etc., for the evening meal, when the system is too much exhausted to digest the more concentrated foods. When men are obliged to take cold lunches in the middle of the day the housewife should see that the lunch basket contains the necessary nourishment in the form of cheese, cold meat, meat or fish sandwiches, hard boiled eggs, a fish or vegetable salad, cold pork and beans, rice pudding, whole wheat bread and b.u.t.ter, a bottle of milk or _strained_ tea or coffee, pie, doughnuts, etc.
Remember, a man working in the open air or in a large building requires food which will not oxidize too quickly, or in other words, food which will keep up the fuel and force necessary for his work.
Supper in such cases should consist of a good broth or well made soup, and the lighter foods; but breakfast and dinner should be more substantial. It is a question of economy to provide suitable food for the wage-earner. The children may be equally well nourished on a less expensive diet, such as whole wheat bread and b.u.t.ter, milk puddings, fruit, green vegetables, cereals, milk, and meat once a day.
On the other hand the individual engaged in sedentary employment, such as book-keeping, teaching, needlework, etc., should dine later in the day, as it leaves a longer interval for digestion, which is much slower when the individual is confined in a close office or work-room, and where little exercise is taken.[5] Care should be taken in planning meals for this cla.s.s to avoid food which requires much oxygen, such as fresh pork, fried food, sausage, warm bread, pastry, griddle cakes, etc. The mid-day meal of a brain worker or business man should be light; a soup, gla.s.s of milk (hot or cold), fruit, bread and b.u.t.ter, vegetable salad, a broiled chop or steak, etc., are suitable for luncheon.
Special attention should be given to the diet of school children. (See p. 153.)
Students and children who are obliged to study at night should, as a rule, take some light nourishment before retiring; a biscuit, a piece of bread and b.u.t.ter, or a gla.s.s of hot milk, is sufficient.
Young girls, who are employed in shops, factories, etc., frequently hurry away to their work in the morning without taking a substantial breakfast. It is needless to say that such action is sure to be followed by a physical breakdown. A gla.s.s of hot milk or an egg beaten and added to a gla.s.s of milk will serve as an occasional subst.i.tute for a more substantial meal, but is not enough to sustain active exercise for any length of time.
Another point to consider in the planning of meals is economy of fuel.
The thoughtful housekeeper will arrange to have food requiring long, slow cooking, such as stews, soup stock, bread, etc., and ironing done by the same fuel. Broiling, toasting, omelets, etc., require a quick fire. It is in the careful consideration of details that economy in both food and fuel may be exercised.
FOOTNOTE:
[5] The teacher may make this clear by comparing the digestion of the two cla.s.ses to the action of the air upon coal in a range with the drafts open and closed, the more rapid combustion, effect of oxygen, etc.
SUGGESTIVE QUESTIONS.
In giving instruction in Domestic Science, the teacher must be careful to explain the meaning of any words used which the pupils would not be likely to understand; for instance, oxidation, combustion, solubility, etc., and many of the terms used in the a.n.a.lysis, such as fermentation, casein of milk, alb.u.men, cellulose, etc. In order to keep the attention of pupils fixed on a subject, frequent ill.u.s.trations and comparisons should be made.