their musical collaborators are doing wonderfully well with these engaging trifles which have lost the odor of suggestive offense and gained of late in wit and musical consequence. Chicago has become quite conspicuous as a manufacturing and producing point of this sort of thing, having developed within a short time "The Burgomaster," "King Dodo," "The Explorers," "The Storks," "The Sultan of Sulu," and "The Wizard of Oz," several of which have taken rank among the best of their kind. To this list might be added "The Liberty

Belles," "Miss Simplicity," "Princess

Chic," "The Little Duchess," "The New Yorkers," "The Chaperones," "Hoity Toity," and a dozen other examples of a like nature, which with two or three excep

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tions are American products. "San Toy," "Florodora" and "The Toreador" were made in England, and it is an interesting fact that Florodora, the most successful of all, earned success chiefly through one number, the double sextette or pretty maiden's song.

It appears from the casual facts that the United States has become self-supporting in the matter of music-comedy, which provides some reason for encouragement. Presently we may be able to supply a greater number of high-class plays and thus meet the demand in another quarter. Our dramatists have already done very well. They possess the necessary talent for good work, but are usually in too much of a hurry. Their work consequently lacks finish.

HE idea of the evolution of species is older than any scientific study of plants and animals. Many an attempt has been made to explain the methods of evolution, but that which produced the most profound impression upon biological thought and investigation was Darwin's attempt to explain the origin of species through natural selection, published more than forty years ago. The general and too often acrimonious discussion that followed the promulgation of this doctrine is now only remembered by the older generation, for the younger have been trained to accept it as a working hypothesis. Of course the only objections to it worth considering were those urged by biologists, for it had to stand or fall as it accorded with their investigations. Even among them there was a period when the idea of natural selection held full sway, and modern biological literature is permeated with it.

Later there followed a period of doubt among biologists as to the sufficiency of natural selection to explain all the phenomena involved in the origin of species, and various supplementary

explanations have been offered. offered. Further progress in the last few years has been very slow because the theories of evolution have been made the subject of speculative discussion rather than of actual investigation.

In 1901, however, there appeared a book entitled "Die Mutationstheorie," by Hugo DeVries of Amsterdam, and it has attracted large and interested attention. Its discussion is just now beginning to find a prominent place in scientific journals, and in modified form this discussion will certainly soon force its way into more popular notice. The great danger is that the "mutation theory," like its predecessor the "theory of natural selection," will be pressed by popular writers and speakers far beyond its original intent. Many see in this theory a new epoch in evolutionary theory; others are unwilling as yet to concede it even an important place. In any event, it is well for intelligent readers to know what it claims as to the origin of species.

Darwin and Wallace's theory of natural selection was presented by using animals chiefly as illustrative material; hence it has

always seemed to be a zoological rather than a botanical theory, though of course applied to all organisms. The mutation theory, on the other hand, comes by way of the plants. It is also interesting to note that the same theory was independently announced in the same year by Korschinsky, under the name "heterogenesis." Korschinsky used the records of gardeners and horticulturists as his facts, while the mutation theory of DeVries is based upon nearly twenty years of experiment and observation.

Mutation or heterogenesis means the sudden origin of a new species, without transition or connecting links; and has sometimes been called "saltatory evolution." The fact of these sudden appearances or "sports" has long been known, and Darwin thought they must be taken into account along with natural selection; but they have been regarded as very exceptional and to be practically disregarded in the origin of species. DeVries makes the point that every species varies within certain limits, in response to external conditions; but that natural selection can develop a variation only to a certain limit, which limit never crosses the species boundary. His numerous and longcontinued experiments seem to show this, and if it be true it is evident that natural selection cannot originate species. The weakness of the theory of natural selection has always been that it could not point to a single experimental proof of one species arising from another through the gradual increase and fixing of a variation by generations of culture. The fact that natural selection can lay hold of variations and perpetuate some and destroy others is evident enough, but the fact that the final cumulative result of this process is a new species has never been proved; and this is the essence of natural selection as the originator of new species. DeVries claims that tatural selection never even fixes a character, as is shown by the fact that after any number of generations of culture reversion occurs; and that the only new forms really permanently established in artificial cultures have arisen through mutation or hybridization.

In short, natural selection can never create anything new; it can only improve within definite and narrow limits. On the other hand, mutation introduces something new which is fixed at the very outset, and will remain as a distinct species if it survives the struggle for existence. These suddenly ap

pearing forms, or "mutants" as they may be called, are selected for perpetuation by natural selection, but natural selection has had no part in producing them. Variability and mutability, therefore, must be distinguished, the former being common to all species within certain limits, the latter the sudden appearance of characters so distinct that they characterize a new species. It would thus seem that most species are fixed and immutable, while all are more or less variable.

Some brief account of the prolonged experiments of DeVries will serve to illustrate both this theory and the nature of his evidence. In his search for a plant in a state of mutability, that is, one capable of giving rise freely to so-called "sports," he found a species of evening primrose, Enothera Lamarckiana, an American species, exactly suited to his purpose. suited to his purpose. It was found naturalized in a field near Hilversum, Holland, in 1875; and when it began to be observed by DeVries in 1886, two new species were discovered by him among the normal forms, and received specific names; and ever since these species have maintained themselves. Since 1886 DeVries has had this area under observation, and has performed almost innumerable experiments in the botanical garden at Amsterdam.

In his book full details are given, but the general results were as follows. Out of 50,000 seedlings successfully grown from seeds of true E. Lamarckiana, 800 were mutants. Out of these 800 mutants, 200 were the same species; that is, the same new species appeared independently 200 times. A number of the mutants, which would doubtless have disappeared in nature, were put under artificial cultivation and remained true generation after generation. The mutations occurred in every possible direction, evidently holding no relation to their common environment, and there were no transitions between the mutants and their parent. The same mutants or new species were also observed to spring from different parents.

These new species as a rule would not have survived in the struggle for existence, but they are new species, from every accepted criterion, and have originated suddenly. As DeVries says: "Once formed, the new species are as a rule at once constant. No series of generations, no selection, no struggle for existence are needed" to establish their characters. Referring to a particu

larly distinct species thus suddenly originated he says: "Evolved with a sudden leap from the mother species, differing from it in general appearance as well as in the character of its various organs, it remained unchanged. It was no rough cast which selection had to correct and polish before it could represent a distinct form; the new type was at once perfect and needed no smoothing, no correction."

In applying these experiments to plants in nature the conclusion is obvious. If several new species arose suddenly from a single plant in the few thousand individuals that came under the observation of a single investigator, how many must have arisen and must be arising from the uncounted individuals in nature? And if one or two of the suddenly appearing species proved to be able to maintain themselves among their neighbors for fifteen years, how many species now living in nature may have had such an origin? It must also be remembered that the same species may appear again and again, in all varieties of condition, thus enormously increasing its chance for establishment.

Aside from the great fact of the origin of species, the chief interest of these experiments lies in their bearing upon the effect of environment. This is entirely eliminated. This is entirely eliminated from the category of causes producing new species, and only operates in the selection of species already produced. It also follows that there is no such thing as purposeful or gradual adaptation; for species are fixed from the start, and disappear or persist as they happen to be adapted to a particular environment. The theory of mutation also brings to the front again the old doctrine of the fixity of species, but in a sense very different from its former statement. The birth of a species is thus as distinct as that of an individual, and to its death it maintains its identity, never "flowing into" other species, but with its own narrow limit of variation.

If the mutation theory of the origin of species be true, we are confronted by a more difficult problem than was presented to us by natural selection. The latter theory laid hold of variations and manipulated them, and it only remained to discover the causes of variation. Many explanations of it have been suggested, from the perennially proposed "influence of environment" to Weismann's suggestion that the sexual method of reproduction found its signifi

cance in the production of variation "to play into the hands" of natural selection. The causes of mutation, however, which is certainly indifferent to environment, are at present shrouded in mystery; but the theory will let loose a flood of investigation that will attack this problem.

Korschinsky's carefully compiled mass of data furnishes strong confirmatory evidence of DeVries theory, for it shows that every new culture-form developed by gardeners and horticulturists has arisen suddenly, and has not been led un to through generations of selected culture. Other observers have added data of species known to have arisen suddenly from others. Wettstein states that several theories as to the origin of species are probable, but that among them mutation is most important. Moll says the book of DeVries is easily the most important contribution to evolutionary doctrine since Darwin's Origin of Species; while Schumann avers that DeVries is the first writer who has really established the theory of evolution.

In the meantime, laymen who are interested in the application of the great principles of biology can await the discussion and investigation of the next few years to test the credibility of this new, apparently substantial, and certainly startling theory.

In closing a recent address at Rotterdam, in which he expounded in a popular way the theory of mutation, DeVries closed with the following significant statement:

"My observations constitute but a first step in a new direction. But that direction is the one demanded by the times. Any advance in our knowledge depends on the possibility of seeing species originate. Of course this does not refer to present species. Such a thing would be as impossible, as absurd, as expecting to witness the birth of an individual already inhabiting the earth. The species living at present are too old. But they may give rise to new ones. There seems to be sufficient reason for suspecting that this is happening at this very moment, and in our immediate surroundings, only we are not aware of it. Such cases must therefore be searched for with great care and patience. Once found, they must be carefully and extensively studied. The one case which I have mentioned shows sufficiently the great treasure of new facts which lies within our reach. All that is necessary is to overcome the first difficulties."

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HE reference recently made, in these pages (see Vol. II, p. 1196), to the disastrous fires that horrified people throughout the country, has suggested the subject of fire-proof construction. There can scarcely be a worse disaster than fire-either in the home or in larger buildings where many people may be congregated. In the latter panic may cause the most deplorable results. No greater benefit could, therefore, be conferred than the more universal introduction of fire-proof construction in all classes of buildings. It is not intended here to treat this subject from the strictly technical standpoint. The object, rather, will be to use the simplest language compatible with the understanding of the systems that have been adopted.

In the past, fire-proof construction has been, practically, a myth. Now, however, science has come to the aid of builders, so that imperfect methods are being eliminated. One encouraging feature, too, is that the building and fire departments of different cities have been taking the matter up. In New York City, for instance, Superintendent Stewart, of the Building Department, called a convention of fire-proof experts from different points, and this. resulted in the formation of a permanent organization, whose efforts will be directed especially to the matter of establishing tests. At the preliminary conference the subject of the fire-proofing of wood was the specific subject considered. This has been of pecuThis has been of peculiar interest in New York, as it would appear that the building laws in regard to the introduction of fire-proof wood have been in some cases evaded, so that in some large buildings worthless material has been introduced. Another evidence of progress is the fact that in Boston, Mr. Edward Atkinson, President of the Manufacturers' Mutual Fire Insurance Company, is working for the

establishment of a school of fire-proof engineering, either independently or in connection with the School of Technology there. "Fire-proof engineering," then, has come to the front as a distinct development of the century.

It is quite as true to say that "no fireproof construction is perfect" as it is to say that "it is possible to make a building fireproof" for both statements have been made. In regard to the first statement, it is impossible to incorporate in construction and necessary finish, absolutely fire-proof materials: in regard to the second, it might be true-if all combustible material were eliminated from construction (and finish); but this is hardly yet possible. To eliminate wood seems to be going against nature. Were wood entirely eliminated, it would, of course, be possible to render a building absolutely fire-proof—as far as materials entering into construction might be concerned. But the expense would be enormous. In such a building as the new Maternity Hospital in New York City, a building as nearly fire-proof as could be planned may be seen.. Other large buildings, in the business centers of cities, may, also, be so constructed that no insurance is placed upon them. Again: a building may even be built according to fire-proof rules, and be still far from fire-proof. Chief Croker, of the New York Fire Department, recently declared that a "building may be legally fire-proof," and still be, practically, a veritable firetrap! This was instanced in the case of the Park Hotel horror (which elicited the remark). This building, as declared by Mr. Atkinson (referred to above) had all the "legal" requirements; but "the gross faults and dangers of the interior fittings made it an easy prey to the fire-fiend. The fire originated at the bottom of an elevator shaft where an accumulation of oil, grease and

(1) THE VAN KANNEL REVOLVING DOOR. lint gave it force from which it was carried to the upper story where the solid roof reflected the heat, smoke and sparks into the front hallway, setting fire to the carpets, to the varnished wood work of the stairways and to the varnish on the doors; also to the stairway between the upper and the next floor, which was of wood, painted bronze to imitate the metal below.. The injury by fire was very small, the loss of life due to panic creating the sensational development. The fire escapes in the wings were ample. Here we see a building that was a very safe one causing loss of life, in the first place by panic and then by suffocation from the smoke derived from the combustible material of the carpets and varnish." All such buildings, as well as schools, etc., should have fire escapes, standpipes (with hose on every floor), electric alarms, extinguishers, ladders, buckets, axes and smoke helmets. But still even with all these appliances the dangers are not eliminated, for, as Chief Croker says, "The trouble is with the fire escapes. The only kind that is safe is an outside stairway of sterling construction, with a hand rail;" and he says "the law should be amended to provide for such." What is known as the revolving door, constructed by Mr. T. Van Kannel, is as nearly as possible the ideal fire escape (1, 2). The fire escape, indeed, though the last appliance to be fixed in buildings, should be the first to be considered in the design. Though

all other means of prevention, repression, and safety, should be earnestly considered.

Inspection of materials and construction should be extended to the inspection of the appliances just referred to: and not only that but to the interior furnishings, after the building has been handed over for occupancy, as well as to the disposal of rubbish and refuse, so that no dangers should occur from their accumulation.

The resistance of buildings to fire depends upon the intensity and duration of the action of the fire, and the effect of the sudden onflow of the extinguishing stream of cooling water from the fire-pipe. Materials should be better studied and experimented with as to their resistance to these attacks. The points of surfaces of greatest danger-those that may be attacked by fire first should receive attention first and last. Materials used in such places should be carefully selected, and then inspected before passed.

Besides using the most approved method or system of construction, the prime consideration should be given to the plan of the building, to insure an arrangement of parts to place the danger points-from which fire might most frequently originate or spread-away from the parts of commonest occupancy. The isolation of these danger points should be accomplished by the insulation (as well as thorough protection) of the elevator-shafts, the stairs, the airshafts, etc., besides the protection of the metal columns and beams, which is sometimes the sole object. All the stair and elevator ways should be enclosed with fireresisting material and have fire-doors; while all openings and blind attics should be cut off from such openings. Well-holes should be stopped at each floor with wire-glass. Stock-racks and packing benches of metal should be used instead of wood, and woven wire instead of wood in partitions. These

OF REVOLVING DOORS.