SCIENCE UP TO DATE.

Lyttelton Times, Volume CXVII, Issue 17096, 19 February 1916, Page 13

SCIENCE UP TO DATE.

THE NEW TEST FOR BLOOD RELATIONSHIP. (By JAMES COLLIER.) Dr George H. F. Nutt-all was at one time an American biologist, but is now a professor in the University of Cambridge, England, and & Fellow of the Royal Society, where he won his spurs by discovering a cure foi too cattle plague known as Texas fever. But lie has"done still greater things. Ho lias discovered that the blood of kindred animals reacts to like tests. He has devised and perfected a system of bloodtesting so delicate and refined that it surpasses the tests that microscopy supplies. By this system lie has been enabled to trace tho relationships between different species in a manner that to skilled biologists seems almost magical. .MECHANISM OF IMMUNITY. Dr Nuttall was stimulated to make this new and original research by recent inquiries into the mechanism o. immunity, when the existence of substances called “ precipitins ” was proved. These pr'oteids are bred in the bodies of animals by the injection of milk, bacterial emulsions, alien blood, cte,, and they derive their'name from the fact that a precipitate is formed when they are added to the substances originally injected. “Thus precipitin formed by the injection of milk will give a precipitate with, milk, but with no other substance, and that formed by the injection of human blood will precipitate only with, human blood, or with the blocd of some closely related animal.” Dr Nuttall was not the discoverer of this property; it had already been used in testing for blood in forensic cases; but he saw in it the, means for demonstrating blood relationships. He and his associates perceived that, by means of the precipitin test a far more accurate scheme of relationships jn the animal kingdom could be thus demonstrated. The research extended over a period of three years, and the results arc remarkable. BLOOD TESTS. But we must first describe the nature of the operations that are carried out in that “ testing shop” (as the electrical 'engineers would call it) in the ancient university of the ions. Like the comparative psychologist, ti • blood-testing biologist procures Ins specimens from all parts of the globe, as many as seventy different persons having provided Professor Nuttall with blood drops and blood-stains. Some were huntsmen, who clipped, a piece of filter paper in the blood of a quarry, or a specimen of blood was collected on blotting-paper, often under great difficulties. and sent by mail from great distances. At the Cambridge laboratory the discoloured bit of paper was soaked in water. From it a clear solution of blood-serum was derived a no placed in a test tube. Now comes the critical operation. If the solution grows cloudy, it discloses the fact that tho blood is that of an animal of a certain species—tiger or leopard, panther or cheetah, and cannot be that of hyena, wolf or dog. Or the blood-stain o'u a floor or a window-sill, on a boot or coin or garment, might he scraped off. A solution of it would he made and subjected to the same test. It would then he found to be human or animal blood, as the case might be. But the most various materials—wallpaper, wood, stone, coal, coke, straw, rubber, linoleum, knives and razors—may supply materials for testing, and that- after a lapse of thirty !\oais. A blood-spot- in the road may he saving or damnatory. THE MAGIC FLUID. The fluid used in spell testings is almost invariably drawn from the veins of a rabbit. But the blood ot ncai 1> every animal has a certain poisonous quality, ,'f it he injected into the vessels of another species. To resist it tlie animal inoculated develops an antisum —an anti-human or anti-feline serum, if it he a man or a cat; no.only mammals, but- birds, reptiles and crustaceans react in a similar manner. This anti-serum is fortified by introducing homoeopathic doses of a foreign blood-serum. In this way the system or the animal inoculated becomes immune. The blood of an immune animal is now used as a test. It- ascertains the presence of the particular type of blood used in developing an anti-serum. Mas human blood injected into the rabbit system? Then the rabbit's blood will now be an efficient test for human blood. TIME-TESTS. Now come the experiments, and how exhaustive they were will appear Lom a brief statement. Professor Nuttall aud his associates tested the blood of some 600 species of animals, from crustaceans to mammals, and they applied no fewer than 16,000 individual tests on the blood of 900 animals. Mitli what results? With amazing results. They have proved the improbable imd confirmed the conjectures of science. Hot drops of anti-serum bo introducetl into the various test-tubes, one after another. Tn some cases the reaction is immediate, and a white precipitate is formed; in others it sets in after a few minutes; in others still there is no reaction at all. It i,s the gradation of these results that justify the experimenter. Thus the precipitation formed by the iniection of human blood will piecipitale oniv with human blood. The reaction is at once loss prompt and less marked in the tubes containing the blood-serum of tho anthropoid apes> It is still milder with baboons, monkeys and marmosets. And m the case ot still lower animals the precipitation is long delayed or null. These results arc startling. H is a striking verification of the consanguinity ot man anil the higher apes that the blood of tho chimpanzee yields 90 per cent as much precipitin with humanised rabbit-scrum is the blood of man himself. The gorilla and the orang come next attci the chimpanzee, and m that ordei. The serum of monkeys, on the other hand, drives only one-third or one-fourrii ot the Can nrecipitin. The experiments throw li'dit on a related problem Did SdiSend from nil O “ suitor or a new? J PP- U 1 show that the Old! World apes are more nearly related to man than are the ew and this is the conclusion of both Darwin and Haeckel. Other relational " among animal species are equally in th. cat butnatur nearer the cat tube. Quite the seal and tho sea-lion Se more closely related to the dog e -Ur The s n als are yet nearer to of the cat tribe. the porpoise. Other discoveries ax© more surprising. The porpoise might he supposed to have affinities with the sea, but no, it seems that the precipitin- of the anti-pig serum shows that the porpoise is closely allied to the ox tribe m general and iL piss in particular. Sad to say, the affinities of its blood serum with human Sod are strong and pronounced. It • nirr that has taken to the water, like the whale, and become oarmvor°US' OTHER RELATIONSHIPS. etiii ntlier relationships are clearly i brought out. Very naturally, lizards

and snakes are found to he closely allied ; a lizard, in fact, is a snake with legs, as the snake is a- lizard without legs. Turtles and crocodiles are somewhat less closely related to one another. The relationship is specially close between birds and mammals. Most readers will remember Huxley’s disputed classification of birds and reptiles, as belonging to the same order, under tlj.o name sauropsidee; so that birds are reptiles with wings, and reptiles arc birds without wings. This classification is but partially borne out by tho blood test. Tho relationship between birds and turtles is particularly close; it is less close between birds and crocodiles; and tho affinities between lizards and snakes on the one- hand and birds on the other are still more remote. Evidently, the ingenious classifier was in good part mistaken. TWO STRTK]NG RESULTS.

Those experiments bring out- results that are hardly loss than astounding. The fact that these tests invariably come true shows that every drop of blood in the human body or iu that of any animal species i.s characteristic. Tho cat or the tiger i.s feline all through; the dog tribe in al! its varieties i.s fundamentally and consistently canine. And so it is with al! other species. The 11 intimate chemical qualities ” of cat and dog. man and ape, have been transmitted through untold thousands of generations unmixed with kindred species. So has the gulf between man and ape since they branched off the common stem of the primates hundreds of thousands of years ago never been bridged 1 , and yet some intangible, quality- in the blood is still found to prove their common origin. THE SUN’S ROTATION.

Some weeks ago we drew attention to the rotation of the sun on its own axis. It is to spectrum analysis that wo owe most of our new lights on these solar movements. The application of the method independently dodevised by Doppler and Fizeau! and known as the Doppler-Fizeau method, has proved that the sidereal rotation of the sun takes plac-o in a little less than twenty-five days at the sun's equator, in 26.6 clays at latitude 30, in 31.2 days at 62 deg and in 3-3.3 da vs at SOdeg. These are enormous differences.

Nor they the only ones. Some eighteen months ago n Dutch astronomer, Hubrecht, applying the method of Dcslandres so fruitful at Mention, discovered that, the two hemispheres of the sun turn as a whole at different velocities—the northern hemisphere rotating at speed's appreciably greater than the sou them hemisphere. Leaving for the present tho theoretical explanations of these strange dyssymmetries. wo note that the host established fact relating to the sunspots is their curious periodicities. About, cverv eleven years 1 hey are nbsciit from the solar disc. Then for three or four years their number and total extent progressively increase. Then they remain stationary for a time, and gradually diminish for six or seven years, till they roach a minimum, when they make a fresh start. We are still completely ignorant of the cause or causes of this strange phenomenon.