ONE MAN’S FOOD, ANOTHER MAN’S POISON.

Otago Witness, Issue 3614, 19 June 1923, Page 59

ONE MAN’S FOOD, ANOTHER MAN’S POISON.

Bv PROFESSOR J. ARTHUR THOMSON. Many of us know or have heard, of people who become very- ill if they eat even a small quantity of egg unawares. Sometimes a rash breaks, out, sometimes an asthmatic attack comes on, sometimes there is colic, and other things occur. There are symptoms suggestive of poisoning. Very diverse animal iood-stuffs bring about the same result—such as milk, mussels, and shrimps: but the sensitive subject, who is of course a rarity, is usually susceptible to one particular thing. Eggs make him violently- ill, but milk will probably help to make him well. A lady who was upset bv a single prawn was quite unaffected by lobster or crayfish. Tire sensitiveness is very- specific, and in genuine cases there is no* influence of imagination, for the symptoms appear when the provocative substance was eaten by mistake along with something else. A man’s life has sometimes been endangered by- eating some soup or the like which contained eggs too well disguised to be detected even by the tongue. —A very particular person.— An interesting point is that the “poisoning,” let us call it, is not induced byvegetables or by- fruits with the sing/e exception of strawberries. In a case reported by Professor Pagniez the susceptible person could enjoy- strawberries provided they- did not come from a particular locality-! Another important point is that the bad effects are not due to anything unwholesome in what is eaten. They are brought about by- perfectly fresh and wholesome food, and must not be confused with the poisoning that sometimes follows mussels or shrimps that were past their best. The symptoms in the two sets of cases are quite different. In the saying, “One man’s food, another man’s poison,” there is perhaps some suggestion of the facts we have just referred to; but any approach to understanding them dales from the beginning of the twentieth century-, and the first steps were due to the distinguished French physiologist, Professor Charles Richet. The interesting story of his discoveries may- be outlined. —Sea-anemones and medicine.— Professor Richet tells us that during a cruise on the Prince of Monaco’s yacht he was impressed by the virulent stinging powers of the strange marine colonyknown as the Portugese Man-of-War, common in warm seas. A glycerine extract of its stinging threals was found to be extremely poisonous to ducks and rabbits into which it was injected. He determined to study the matter further. But when he went back to France be could not obtain a supply of Portugese Man-of War, so he made a

glycerine extract of the tentacles of sea- 1 anemones (Actinia?) —those common sting- I ing animals that nestle like flowers in the niches of the seashore-pools. Along with M. Portier, who had been with him on the cruise, he injected the sea-anemone extract into dogs and found that it was very fatal. To some of the dogs which recovered, haying received only a little poison, the experimenters gave, alter three weeks, a second dose, and that a very minute one. They- found to their surprise that the animals died in a few minutes. To the hyper-sensitive condition of the animal Richet applied the term anaphylaxis. It was soon shown that the injected substance which brought on the hypersensitiveness when injected into an animal need not be poison; it may be white of egg, or blood-serum, or milk, or muscle extract, and so forth. The animal gets a good injection, and its blood answers back, forming, it is believed, a counter-active or anti-body-. After some time has elapsed (the “incubation period”), the animal receives a second dose, but a very minute one, which would not have any effect at a.ll if the creature were not hyper-sensitive. Yet the result is a violent attack, often ending fatally. So to speak, the animal receives a hair of the dog that bit it, and that hair maykill. This is anaphylaxis. -—Guinea-pigs and murder-trials.—-Before we inquire into the physiology of anaphylaxis, let us give some more examples. It is easy to make guinea-pigs hyper-sensitive to minute injections of different kinds of blood. After treatment A will answer back to horse's blood, B to bullock’s, C to sheep's, D to dog’s, E to man’s. Now, this affords a quick and certain wav of deciding whether a small quantity of blood, even from a stain, is, let us say, a horse’s or a man’s. A solution of the blood is injected into the guinea-pigs A —E ;if A reacts, the bloodstain was equine, if E reacts, the bloodstain was human. A strange rope to hang a man with! Some guinea-pigs were subjected to injections of the muscle of a human mummy. After an interval they- were tried with muscle-extracts from various animals, but they reacted only to’ human muscle, “thus proving, if proof were needed, that *.he chemical composition of the human body has not changed appreciably in the last three thousand years. —Hav-fever. — Slime people suffer greatly from hay - fever, which is marked by ‘ cold in the head,” sore eves, headache, and feverishness. Now, it has been proved that this is due to the inhalation of floating pollen grains from the air. In spring hay-fever the provocatives are usually tne pollen e-rains of grasses; in autumn they- usuallycome from other plants such as golden rod. But here we have to do with an anaphylactic phenomenon,” for be sufferer from what is a troublesome ichosyncrasv once had a had infection and remains in a condition so susceptible, so hyper-sensitive, that a mere whiff oi tne pollen-laden air suffices to bring on an attack of bay-fever. If the irritation spreads to the windpipe and bronchial tubes the patient maybecome asthmatic. It may- be mentioned that hav-fever can be induced in man and beast by injections of extract of grass pollen, and that there are now counteractive treatments which may save tne patient from ever being troubled again. It seems a far cry from sea-anemones to hav-fever, but the logical chain is clear. Primroses and poison-vines. ■ gome people, including professional r-ardeners, are extraordinarily sensitive to contact with a common cultivated primrose, Primula obconica, which looks innocence itself. After they have touched the plant a rash breaks out on then skin and there is great discomfort. J his ar-ain is anaphylactic; a bad injection once, a persistent hypersensitiveness, and then’ a mere touch brings on an irritation quite out of proportion to the cause. The simplest remedy is to banish the obnoxious obconica and cultivate somethin<T el«e In a deadlier way the same thin” is illustrated bv the poison vine or poison ivv of North America, sometimes planted in British gardens m mistake for a Virginia creeper. It is one of the sumachs (Rhus toxicodendron), and contains a verv poisonous oil, iruscroscopic droplets of ' which must be earned off on dust particles, for susceptible people are affected from some distance. It is plain that the old story of the upas tree has a grim basis of fact. And the poison ivy- does not stand alone. A Hair of the Guinea Pig.— Dr Markley reports a very curious case of a lady who was subject for years to a rash and eruptions on her face, neck, and forearm. All sorts of treatments were tried, including, as the author oi “The Doctor’s Dilemma” would be pleased to learn, the removal of the appendix. But all in vain. It was finally discovered that the irritation was due to contact, with a guinea pi S which the lady s little bov kept as a pet. the application ot a single hair was enough to provoke a reaction, but the hyper-sensitiveness was strictlv local, being manifested only on those parts of the skin which had been previously affected. . Cases 'like the guinea-pigs hair, tne primula, and the strawberry are somewhat of the nature of curiosities, and it must be understood that anaphylactic phenomena mav be of great importance without being "in any way picturesque. They may occasionally occur, for instance, in connection with drugs such as quinine and anti-pyrine or in connection with serum* treatment. The hvpersensitiveness or intolerance that develops in susceptible people is sometimes extraordinary. A mere whiff from a bottle of dry " ricine may bring on violent symptoms, and a pharmaceutical chemist at a trial told the jury that he could not even open a bottle of ipecacuanha powder without weeping and sneezing

A very interesting fact is that if the blood or blood-serum of an anaphylactic animal bo injected into a. normal individual the result is to induce anaphylaxis in the recipient, and this takes place very rapidly. Moreover, an anaphylactic mother guinea-pig may have young ones which are born with her peculiarity—an evidence of the intimacy of the ante-natal partnership. But this congenital anaphylaxis does not last. Ttiis is a path that we cannot follow except for a little way. It is too steep for us. The preliminary- injection of some substance affects the animal's blood, and during the period of “incubation” tho blood answers back by forming a counteractive or anti-body. It is tile presence of this anti-body that makes the animal so liyper-sensitiye,' and we have seen that the injection of its blood-sornm into a normal individual may make the latter livpersensitive in a few hours.—John o’ London’s Weekly.