always seemed to be a zoological rather than 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. 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. 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 sclection 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 natural 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 cre ate anything new; it can only improve with 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 in dividuals 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 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." Fire-Proof Construction of Buildings. TH THE LATEST IMPROVEMENTS FOR THE PROTECTION OF LIFE. BY ROBERT C. AULD. 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. establishment of a school of fire-proof engi- 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 Fire Insurance Company, is working for the where an accumulation of oil, grease and 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 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 (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 not coming within the strict domain of fireproof construction, yet the fire escape, and 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 are recommendations of the Philadelphia Board of Underwriters, which body also recommends auxiliary pumps in connection with the present fire pumps, in order to control the latter automatically and maintain an efficient pressure. form of fire-proof construction may be utilized. In the public building, such as a school, a library, a hall, a municipal building, all of which should be constructed upon the monumental plan, of, stone, of moderate height, and uniform design on all sidesthus creating what should be an historical addition to the site, complete fire-proof construction is also possible. The dangers in these are the open spaces for stairways, hallways, etc., as well as the larger use of ornamental wood. But it is interesting to note how massive ornamental effect can be introduced into public buildings by what is called "false" construction of a fire-proof nature. If the interior finish could be entirely of materials wrought in stone, cement, plaster, metal or glass; and all doors made fireproof, and all windows fitted with fire shutters, some approximation would be made to an absolutely fire-proof structure. In such a building each room or apartment could be considered a unit by itself. This must be more and more recognized as the cardinal, as well as guiding, principle of fire-proof construction. Should fire break out in such room or apartment, being a unit, the fire would consume whatever was combustible therein and spend itself. To keep the fire, then, where it originates, and to prevent its spreading from such locationthat must be the aim of builders and designers. It is possible to apply materials in such manner that the combustible contents of such unit might be so consumed therein without endangering those beyond. The exclusion of all combustible material, however, is, as indicated, hardly yet in sight: and therefore the greater care should be exercised in the introduction of what amount of inflammable material must be used. The inclusion of some wood should not increase the immediate danger, because the different parts of the building should be made to take care of themselves. Constructed upon this principle, the building becomes an assemblage of individual parts, self-protective in themselves. All parts giving access to the same, or required for light or air or conduit, should be insulated, and, where possible, isolated. As to the materials entering into construction, the original material, wood, must be considered. As a material for a modern structure, however, wood is becoming obsolete. It has been the dream of chemists to discover some substance that would render wood fire-proof. Since the great fire in London (1666) the subject has been studied; and even previously the files of the British patent office demonstrate the attempts made in this direction. But still wood remains the "boon companion of fire." When a Western professor, in this country, announced that phosphate of ammonia was a substance that rendered wood non-inflammable, the announcer forgot to add that the real difficulty was not in applying this substance to the wood but in insuring its retention in its tissue. In common language the substance when applied to the wood quickly "evaporated." Perhaps the nearest approximation to a trustworthy fire-proof wood is that being produced, by an electric process of impregnation, by Max Bachart of New York City, whose product has stood searching tests. All buildings into which stone, brick and steel and its accompaniment, cement, enter, may be made "fire-proof:" but a "frame" building, under no conditions, could be made so. Here comes into consideration the question of the possibility of creating a new form of building, a new mode of construction, for private homes, that might be rendered fire-proof. If the metal supports were fashioned light enough, this would be possible; the expense would be the only thing to consider. The office-building, as well as the large store and factory, are now more within the domain of the civil engineer than of the architect; and in them the most approved The modern fire-proof material, of strength and resistance, is steel. Steel and iron are liable, however, to corrosion even with the most approved protective casing. The most sanguine do not give a steel building a life of more than fifty years at the longest. This is an estimate that is easily made, for none who make it expect to see it disproved. The collapse of a steel constructed building seems, to the engineer today, such a "far-off event," that it is hardly taken into account-except by alarmists. Mr. J. H. Richardson, a studious authority, has stated to the writer the fact (first pointed out by him) that in British and other museums, the bronze statues, of early |