More Science From an Easy Chair

arguments put forward in its favour by its advocates are foolish or erroneous. Some of the arguments put forward in favour of the exclusive

. That question, as well as the question of the advantage of a mixed diet of animal and vegetable substances, and the best proportion and quantity of the substances so mixed, must be settled, as also the question as to the harm or good in the habitual use

heir young and are called "mammals" (for which word perhaps "beasts" is the nearest Anglo-Saxon equivalent) show in different groups and orders a great variety in their teeth. The birds of to-day have no teeth, the reptiles, amphibians, and fishes have usually simple conica

ncisors. can. s. Upper canine, corner-tooth, or dog-tooth. can. i. Lower canine. m. s. The four upper mola

tiger's skull. inc. i. Lower incisors. inc. s. Upper incisors. can. i. and can. s. Lower and upper

rinding, transverse ridges of enamel are present on the cheek-teeth, as in elephants, cattle, deer, and rabbits (see Figs. 8, 17, 19). Truly carnivorous animals, which eat the raw carcases of other animals, have a different shape of teeth. Not only do they have large and dagger-like canines or "dog-teeth" as weapons of attack, but the cheek-teeth (very few in number) present a long, sharp-edged ridge running parallel to the length of the jaw, the edges of which in corresponding upper and lower teeth fit and work together like the blades of a pair of scissors. The cats (including

them straight off (Pl. VI). They are broad, square-surfaced teeth, with four or fewer low rounded tubercles fitted to crush soft food, as are those of monkeys (see P

arnt to cook the meat before he ate it. He thus separated the bone and intractable sinew from the flesh, which he rendered friable and divisible by thorough grilling, roasting, or baking. To eat meat thus altered, both chemically and in texture, is a very different thing from eating the raw carcases of large animals. Man's teeth are tho

y disqualified from any form of meat-diet, most other land-mammals can be induced, without harm to themselves, to take a mixed diet, even in those cases where they do not naturally seek it. Pigs, on the one hand, and bears, on the other, tend naturally to a mixed diet. Many birds, under conditions adverse to the finding of their usual food, will change from vegetable to animal diet, or vice-versa. Sea-gulls normally are fish-eaters, but some will eat biscuit and grain when fish cannot be had. Pigeons have been fed successfully on a meat diet; so, too, some parrots, and also the familiar barn-door fowl. Many of our smaller bird

wn species. This is a startling theoretical justification-from the purely dietetic point of view-of cannibalism. It is, however, of no conclusive value; the only method which can give us conclusions of any real value in this and similarly complex matters is prolonged, full

smells and poisons in them, just as they do in foods of animal origin. It is true that on the whole more varieties of vegetable food can be kept dry and ready for use by softening with hot water than is the case with foods prepared from animals. This is only a question of not keeping food too long or in conditions tending to the access of putrefactive bacteria. It is, on the whole, more usual and necessary, in order to render it palatable, to apply heat to flesh, fish, and fowl than to fruits. And it is by heat-heat of the temperature of boiling water-applied for ten minutes or more, that poison-pr

cur in the apes nor in any other living mammal, although it is found in some extinct herbivores-the Anoplotherium and the Arsin?itherium. The shape of the arch formed by the row of teeth sho

ber. The word "molar" is often used to include the five cheek-teeth on each side of each jaw, but more strictly the anterior bicuspid teeth are called "pre-molars," and the thr

crown of the most anterior (or "first") molar of the upper jaw has four cusps, tubercles, or cones on it. It is "quadri-tuberculate." The second and third molars of the upper jaw have three such prominent tubercles (excluding a row of small tubercles on the hinder margin of the second); they are, in fact, tri-tuberculate; whilst the two hindermost molars of the lower jaw have four tubercles and are called quadri-tuberculate. The first molar (M1) of the lower jaw has in this specimen five

ot for cutting lumps of bone or raw flesh, as are the molars of the clouded tiger (identical with those of all species of the genus Felis), shown in Figs. 21 and 22, pp. 103,

and must certainly be of value as weapons of attack-which man's are not. Connected with the large size of the canines is the presence of a gap (or "diastema" as it is called) between the four front teeth or incisors of the upper jaw and the upper canine-which allows the lower canine to fit in front of the upper canine when the jaw is closed. The number of the tubercles or cones on the molars (the two smaller pre-molars and the three hinder large molars) can be compared in detail in these beautiful drawings from Professor Selenka's work, which are the most careful and perfect which have ever been published. The agreement of these teeth in man and the gibbon is very close: but there are differences. The first, or most an

y, man and the gibbon-to food of the same mechanical quality, and this undoubtedly is fruit and nuts. Nevertheless such a form of tooth is

d not make cooked meat a portion of their diet, with the purpose of maintaining themselves in as healthy and vigorous a state as possible. Do not let us forget that ancient Pal?olithic cave-men certainly made use of fire to cook their meals of animal flesh, and that probably this use of fire dates

the business of the State, it is obviously the duty of the Government to investigate this matter and arrive at a decision. It can be done by the Government, and only by the Government. The Army Medical Department is fully capable, and, I am told, desirous, of undertaking this investigation. Five hundred soldiers in barracks would find it no hardship, but an agreeable duty (