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QUEEN MARY
686
special frame. For the patient who is recovering from respiratory paralysis and who is able to get out of the tank respirator for twenty minutes or half an hour at time an efficient cuirass is invaluable. He can lie sit as he chooses, his limbs are free and accessible when physiotherapy is required, and the bedpan offers no fears ; the psychological benefit may be imagined. Though the cuirass cannot be expected to replace the tank respirator in acute or severe phases of paralysis, it can nevertheless do much to mitigate distress and aid patients on the road to recovery if this is to be their lot. The perfect respirator is still far from being attained, and it is perhaps only those doctors, nurses, and engineers who are working on the problem that appre-
beaters necessary for the aeration process, standard equipment can be supplied, and this machine, handling up to a quarter-sack at a time, will complete the doughing without removing the batter from the pan.
a
or
ciate the enormous difficulties encountered. For their part in the evolution of apparatus the names of DRINKER, BOTH, NUFFIELD, and BowERS will long be held in esteem.
Annotations QUEEN
MARY
QUEEN MARY, unlike the consorts of any of our Kings since Tudor times, was born and brought up in this country ; and in her long years of public life she became almost a national possession. Her childhood was spent in one era and her old age in another ; but through all vicissitudes she appeared consistent, unshaken, and still interested. In the strengthening of the Monarchy during the reign of George V her part was perhaps as great as her husband’s ; and their example of duty and virtue was effective because the King and Queen were liked as well as respected. That liking and respect are reflected in the impression made by her death. To most of us Queen Mary had been Queen Mary since the days of our childhood ; and the longer our knowledge of her the more we must feel that our world has lost something solid and enduring. THE AERATION PROCESS
- ON March 21 we mentioned the aeration of dough a possible alternative to the use of nitrogen trichloride (agene) or other chemical improvers used in the preparation of flour. We are now informed that for the past eighteen months Beatties Bakeries of Glasgow, the largest bakers in Scotland, have been making a substantial proportion of their bread by an " aeration process," and that in their new factory at Dundee they have dispensed entirely with chemical improvers or bleachers. In both Glasgow and Dundee bread made by this method is being sold to the public. In the new process half the flour used in the final dough is whipped with water at very high speeds for about five minutes. During that period the whipped dough, or batter, absorbs from the atmosphere so much oxygen that it becomes an oxidising agent ; and when it is removed from the mixer and placed in a normal doughkneading machine it bleaches and improves the other half of the flour which has not been subjected to aeration.. Violent agitation of the batter at very high speeds is needed to procure oxygenation, and this agitation is achieved by two statically balanced blades. as
The high-speed mixing machine, built - by the Morton Machine Company Ltd., of Wishaw, Scotland, is employed with a process patented by Joseph Rank Ltd., using untreated and unbleached flour. The one-sack (280 lb. of flour) machine is not designed for doughing, but is capable of feeding a number of the orthodox types of dough-kneaders. Small bakeries have been catered for with an extra heavy vertical mixer incorporating special features. Besides
Before chemical improvers came into use, some forty " years ago, flour was stored or aged " for a period so Those who have as to improve its baking qualities. devised the aeration process claim that in a few minutes, under full control, this reproduces the alteration of the flour which formerly took place during the period of storage. In our last issue, however, Prof. A. C. Frazer suggested that the proteins of wheat may perhaps be denatured as much by this vigorous physical treatment as they are by treatment with chemical improvers such as
agene.
RESISTANCE TO TUBERCULOSIS VACCINATION with B.C.G. and’other attenuated strains of tubercle bacilli induces a limited immunity in experimental animals. With small groups of vaccinated and unvaccinated mice the difference in survival time after infection is too slight to be an accurate measure of immunity. But estimates of the numbers of tubercle bacilli in the lungs and spleen under standard experi. mental conditions show much greater differences. Dubos and his colleagues 12 found that the average survival time of a group of vaccinated mice was 27 days, compared with 19 days for the unvaccinated animals ; but the number of bacilli in the lungs two weeks after infection was 200 times as great in the unvaccinated as the vaccinated. With this more delicate test they showed that immunity was directly related to the extent to which the attenuated strain multiplied before the challenge infection. Avirulent strains do not multiply in the tissues, nor, in the relatively small doses used, did they produce Small doses of vaccine any detectable immunity. required longer to produce- immunity than large doses, and the more highly attenuated strains, multiplying more slowly in the tissues, were least effective. If multiplication was impeded by treating the mice with isoniazid after vaccination the development of immunity could be retarded or completely prevented. As far as is known, tubercle bacilli do not produce any substance essential for the production of immunity It seems likely, thereduring their multiplication. fore, that immunity is a response merely to the presence of sufficient numbers of bacilli in the tissues. It might, then, be possible to immunise an animal by the injection of larger numbers of dead bacilli ; and there have been many contradictory reports on this point. Dubos and his colleagues3 have now reinvestigated the problem. They found that vaccination with 0.2 to 1-0 mg. of phenol-killed bacilli did produce immunity in mice-an immunity shown both by increased survival time and decreased bacterial content of the spleen and lungs. There was no evidence that the level of immunity was related to the virulence of the strain, and vaccines produced from avirulent bacilli appeared as effective as those from virulent or attenuated strains. The immunity was of the same order as that resulting from vaccination with smaller doses of a living attenuated strain. It seems that the immunising factor is not related to the constituent of the bacilli responsible for virulence. The differences in immunising properties of living bacilli of different virulence appear to depend only on the rapidity with which they multiply in the body. The factor was destroyed by heat, but persisted after the cells had been disintegrated and rendered non-acid-fast by grinding with concentrated phenol. Dubos et al. suggest that it may be possible to separate it from other constituents of the bacilli, especially from " cord factor," which is 1. Pierce, C. H., Dubos, R. J., Schaefer, W. B. J. exp. Med. 1953, 97, 189. 2. Dubos, R. J., Pierce, C. H., Schaefer, W. B. Ibid, p. 207. 3. Dubos, R. J., Schaefer, W. B., Pierce, C. H. Ibid, p. 221.
special frame. For the patient who is recovering from respiratory paralysis and who is able to get out of the tank respirator for twenty minutes or half an hour at time an efficient cuirass is invaluable. He can lie sit as he chooses, his limbs are free and accessible when physiotherapy is required, and the bedpan offers no fears ; the psychological benefit may be imagined. Though the cuirass cannot be expected to replace the tank respirator in acute or severe phases of paralysis, it can nevertheless do much to mitigate distress and aid patients on the road to recovery if this is to be their lot. The perfect respirator is still far from being attained, and it is perhaps only those doctors, nurses, and engineers who are working on the problem that appre-
beaters necessary for the aeration process, standard equipment can be supplied, and this machine, handling up to a quarter-sack at a time, will complete the doughing without removing the batter from the pan.
a
or
ciate the enormous difficulties encountered. For their part in the evolution of apparatus the names of DRINKER, BOTH, NUFFIELD, and BowERS will long be held in esteem.
Annotations QUEEN
MARY
QUEEN MARY, unlike the consorts of any of our Kings since Tudor times, was born and brought up in this country ; and in her long years of public life she became almost a national possession. Her childhood was spent in one era and her old age in another ; but through all vicissitudes she appeared consistent, unshaken, and still interested. In the strengthening of the Monarchy during the reign of George V her part was perhaps as great as her husband’s ; and their example of duty and virtue was effective because the King and Queen were liked as well as respected. That liking and respect are reflected in the impression made by her death. To most of us Queen Mary had been Queen Mary since the days of our childhood ; and the longer our knowledge of her the more we must feel that our world has lost something solid and enduring. THE AERATION PROCESS
- ON March 21 we mentioned the aeration of dough a possible alternative to the use of nitrogen trichloride (agene) or other chemical improvers used in the preparation of flour. We are now informed that for the past eighteen months Beatties Bakeries of Glasgow, the largest bakers in Scotland, have been making a substantial proportion of their bread by an " aeration process," and that in their new factory at Dundee they have dispensed entirely with chemical improvers or bleachers. In both Glasgow and Dundee bread made by this method is being sold to the public. In the new process half the flour used in the final dough is whipped with water at very high speeds for about five minutes. During that period the whipped dough, or batter, absorbs from the atmosphere so much oxygen that it becomes an oxidising agent ; and when it is removed from the mixer and placed in a normal doughkneading machine it bleaches and improves the other half of the flour which has not been subjected to aeration.. Violent agitation of the batter at very high speeds is needed to procure oxygenation, and this agitation is achieved by two statically balanced blades. as
The high-speed mixing machine, built - by the Morton Machine Company Ltd., of Wishaw, Scotland, is employed with a process patented by Joseph Rank Ltd., using untreated and unbleached flour. The one-sack (280 lb. of flour) machine is not designed for doughing, but is capable of feeding a number of the orthodox types of dough-kneaders. Small bakeries have been catered for with an extra heavy vertical mixer incorporating special features. Besides
Before chemical improvers came into use, some forty " years ago, flour was stored or aged " for a period so Those who have as to improve its baking qualities. devised the aeration process claim that in a few minutes, under full control, this reproduces the alteration of the flour which formerly took place during the period of storage. In our last issue, however, Prof. A. C. Frazer suggested that the proteins of wheat may perhaps be denatured as much by this vigorous physical treatment as they are by treatment with chemical improvers such as
agene.
RESISTANCE TO TUBERCULOSIS VACCINATION with B.C.G. and’other attenuated strains of tubercle bacilli induces a limited immunity in experimental animals. With small groups of vaccinated and unvaccinated mice the difference in survival time after infection is too slight to be an accurate measure of immunity. But estimates of the numbers of tubercle bacilli in the lungs and spleen under standard experi. mental conditions show much greater differences. Dubos and his colleagues 12 found that the average survival time of a group of vaccinated mice was 27 days, compared with 19 days for the unvaccinated animals ; but the number of bacilli in the lungs two weeks after infection was 200 times as great in the unvaccinated as the vaccinated. With this more delicate test they showed that immunity was directly related to the extent to which the attenuated strain multiplied before the challenge infection. Avirulent strains do not multiply in the tissues, nor, in the relatively small doses used, did they produce Small doses of vaccine any detectable immunity. required longer to produce- immunity than large doses, and the more highly attenuated strains, multiplying more slowly in the tissues, were least effective. If multiplication was impeded by treating the mice with isoniazid after vaccination the development of immunity could be retarded or completely prevented. As far as is known, tubercle bacilli do not produce any substance essential for the production of immunity It seems likely, thereduring their multiplication. fore, that immunity is a response merely to the presence of sufficient numbers of bacilli in the tissues. It might, then, be possible to immunise an animal by the injection of larger numbers of dead bacilli ; and there have been many contradictory reports on this point. Dubos and his colleagues3 have now reinvestigated the problem. They found that vaccination with 0.2 to 1-0 mg. of phenol-killed bacilli did produce immunity in mice-an immunity shown both by increased survival time and decreased bacterial content of the spleen and lungs. There was no evidence that the level of immunity was related to the virulence of the strain, and vaccines produced from avirulent bacilli appeared as effective as those from virulent or attenuated strains. The immunity was of the same order as that resulting from vaccination with smaller doses of a living attenuated strain. It seems that the immunising factor is not related to the constituent of the bacilli responsible for virulence. The differences in immunising properties of living bacilli of different virulence appear to depend only on the rapidity with which they multiply in the body. The factor was destroyed by heat, but persisted after the cells had been disintegrated and rendered non-acid-fast by grinding with concentrated phenol. Dubos et al. suggest that it may be possible to separate it from other constituents of the bacilli, especially from " cord factor," which is 1. Pierce, C. H., Dubos, R. J., Schaefer, W. B. J. exp. Med. 1953, 97, 189. 2. Dubos, R. J., Pierce, C. H., Schaefer, W. B. Ibid, p. 207. 3. Dubos, R. J., Schaefer, W. B., Pierce, C. H. Ibid, p. 221.