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TOWN ↔ COUNTRY
609
Annotations
at
regular
were
intervals afterwards.
Finally
the
coverslips
detached, stained by Leishman’s method and It was found that after 80 minutes the count had fallen to between 60 and 20% of the count ; the final figure depended on the anti-
examined.
⇆
COUNTRY TOWN THE evacuation of London school-children is now two years old, and in the balance-sheet presented to the education committee of the London County Council on Nov. 5 the chairman was able to show a reasonable profit-and-loss account. What the children have missed in the way of formal education they have gained in mental and physical vigour and a new breadth of outlook. The constant ebb and now of children and teachers necessitates the frequent reorganisation of classes, and the scarcity of new entrants makes it difficult to maintain separate departments for juniors, seniors and infants. But if classes have a wider range, they are smaller than in London and there is more scope for individual study. At school the children may find their quarters cramped and the sanitary arrangements inadequate according tó London standards, but good food, early bedtime and fresh air have improved their health, and the town children have a better attendance record than the local children and show more resistance to epidemics. If there is a shortage of school books and equipment, nature study and practical geography are attractive new lessons ; if the gym, playground and swimming baths are small or non-existent, and if equipment for domestic science, art and crafts is lacking, the children have found new
such as milking, bee-keeping, poultry-keeping and, above all, gardening. To many it was news that peas, beans and cabbages have a history that goes beyond the the boy greengrocer in Deptford High Street, but now from Bermondsey brags about his " sprarts " and makes his plot an economic as well as a horticultural success. No-one can read the report without reeling admiration for the London teachers, who now often look after their young charges in and out of school hours and during the holidays. The closer relationship between teachers and children has been one of the gains of evacuation. The teachers are often leading rather lonely lives, isolated from books, professional contacts and home ties ; yet it is due to their enterprise that the children have sometimes been able to contribute to the life of the community, and school concerts and displays of handiwork have been warmly welcomed by the country dwellers. But the country does not seem to have made many lasting converts. When the rest of their family remains in town, it is only natural that the children should return when they leave school, and in an inquiry among 1500 " leavers i, less than’a quarter remained in the reception area, and of these very few were taking up farming or agricultural work.
ploys
THE
STICKINESS OF PLATELETS
IT is a classical observation that blood-platelets and white cells collect at the point of injury of a blood-vessel and there form a thrombus ; Osler remarked on the way platelets stick to foreign particles. But although methods have been described for estimating the adhesiveness of white cells, no-one has tried to measure this property in platelets. Payling Wright1 has devised an ingenious method of following the changes in the stickiness of blood-platelets that are caused by the use of various anticoagulants, and incidentally she has suggested an explanation of the disappearance of platelets in -stored blood. Specially shaped glass bulbs were used which had carefully ground apertures at either side ; these apertures were sealed with coverslips held in place with soft paraffin. Blood was collected in an oiled syringe, mixed with dry anticoagulant in a waxed beaker, and then transferred to the glass bulbs which were
steadily
rotated
a motor. For control, some of the put into a bulb coated on the inside with soft paraffin. The platelets were counted by a standard method before the blood was put into the bulbs and then
blood
by
was
1.
Payling Wright, H. J. Path. Bact. 1941, 53, 255.
platelet
original coagulant used, but still more on the the anticoagulant. Oxalate, heparin,
concentration of chlorazol pink, and chlorazol blue were tried. With a concentration that would just prevent clotting, the platelet count after 80 minutes’ rotation fell to 20-25% of the initial count with all these anticoagulants ; but when concentrations of eight or more times minimal were used the final count in oxalated blood was about 60% of original and about 45% with the other anticoagulants. In the control bulbs there was only a slight fall in the platelet count. When the stained coverslips were examined, the missing platelets were found sticking to the glass, and it was noticed that at the higher anticoagulant concentrations the platelets tended to adhere only to the glass and not to each other. Payling Wright concludes that anticoagulants reduce the stickness of platelets, possibly by reducing fibrin formation on their surfaces. The disappearance of platelets in stored blood is due to their adherence to the walls of the storage bottles’and not to disintegration, for had this happened clotting might well have been expected when the anticoagulant concentration was minimal and the fall of the platelet count large ; but no clotting occurred. This technique can clearly be extended to pathological problems. Are the bloodplatelets less sticky in purpuras’? Can " thrombasthenia " be demonstrated ? Will the answers help, us to decide between the orthodox school who think that the stickiness.of blood-platelets assists the actual plugging of injured blood-vessels and those who hold that they only help to initiate clotting in the shed blood.2 This method might also be used to seek materials, possibly plastics like Perspex, that platelets will not stick to and could be used for the collection of platelet-containing blood.
TOO MUCH OF A GOOD THING NATURE has been none too bountiful with her supplies of the vitamins,.as the widespread incidence of deficiency diseases shows. The possibility of overdosage, therefore, hardly arose before the interference of man led to the detection, isolation and finally synthesis of several of their number. After the synthesis of calciferol by the irradiation of ergosterol, the too energetic exhibition of this substance to infants and children led to several instances of undue calcification and occasional death.34 Hypervitaminosis A has not yet been described in humans, although it can be produced experimentally in rats.9 Overdosage is more readily to be expected with these fat-soluble vitamins, which are not easily elimin ated by the body, than with the water-soluble factors, excess of which is readily excreted in the urine. Nevertheless, a large dose of a water-soluble vitamin might cause for a short time a high concentration in the blood and so possibly lead to untoward symptoms. This, for example, is true of nicotinic acid. Doses of more than 50 mg. by mouth or 10 mg. intravenously may produce flushing and irritation of the skin, and occasionally gastrointestinal symptoms.6 These effects are transitory ; the concentration of the vitamin in the blood rapidly falls as the excess, which is not metabolised or stored, is excreted by the kidneys. Whether large doses of the other water-soluble factors produce undesirable reactions is not certain. It has been suggested that intense treatment with vitamin B1may give rise to symptoms akin to those of herpes zoster-intense irritation of the skin and a burning pain in peripheral nerve areas.7 2. See Lancet, May 3, 1941, p. 574. 3. Hess, A. F., Lewis, J. M., and Rivkin, H. J. Amer. med. Ass. 4. Harris, L. J. Lancet, 1932, 1, 1031. 1930, 94, 1885. 5. Takahashi, Nakamiya, Kawakimi and Kitasato, Sci. Pap. Inst. phys. chem. Res 1925, 3, 81. 6. E.g., Spies, T. D., Bean, W.B. and Stone, R.E. J. Amer. med. A 1938, 111, 584. 7. Steinberg, C. L. Amer. J. digest. Dis. 1938, 5, 680.
.
Annotations
at
regular
were
intervals afterwards.
Finally
the
coverslips
detached, stained by Leishman’s method and It was found that after 80 minutes the count had fallen to between 60 and 20% of the count ; the final figure depended on the anti-
examined.
⇆
COUNTRY TOWN THE evacuation of London school-children is now two years old, and in the balance-sheet presented to the education committee of the London County Council on Nov. 5 the chairman was able to show a reasonable profit-and-loss account. What the children have missed in the way of formal education they have gained in mental and physical vigour and a new breadth of outlook. The constant ebb and now of children and teachers necessitates the frequent reorganisation of classes, and the scarcity of new entrants makes it difficult to maintain separate departments for juniors, seniors and infants. But if classes have a wider range, they are smaller than in London and there is more scope for individual study. At school the children may find their quarters cramped and the sanitary arrangements inadequate according tó London standards, but good food, early bedtime and fresh air have improved their health, and the town children have a better attendance record than the local children and show more resistance to epidemics. If there is a shortage of school books and equipment, nature study and practical geography are attractive new lessons ; if the gym, playground and swimming baths are small or non-existent, and if equipment for domestic science, art and crafts is lacking, the children have found new
such as milking, bee-keeping, poultry-keeping and, above all, gardening. To many it was news that peas, beans and cabbages have a history that goes beyond the the boy greengrocer in Deptford High Street, but now from Bermondsey brags about his " sprarts " and makes his plot an economic as well as a horticultural success. No-one can read the report without reeling admiration for the London teachers, who now often look after their young charges in and out of school hours and during the holidays. The closer relationship between teachers and children has been one of the gains of evacuation. The teachers are often leading rather lonely lives, isolated from books, professional contacts and home ties ; yet it is due to their enterprise that the children have sometimes been able to contribute to the life of the community, and school concerts and displays of handiwork have been warmly welcomed by the country dwellers. But the country does not seem to have made many lasting converts. When the rest of their family remains in town, it is only natural that the children should return when they leave school, and in an inquiry among 1500 " leavers i, less than’a quarter remained in the reception area, and of these very few were taking up farming or agricultural work.
ploys
THE
STICKINESS OF PLATELETS
IT is a classical observation that blood-platelets and white cells collect at the point of injury of a blood-vessel and there form a thrombus ; Osler remarked on the way platelets stick to foreign particles. But although methods have been described for estimating the adhesiveness of white cells, no-one has tried to measure this property in platelets. Payling Wright1 has devised an ingenious method of following the changes in the stickiness of blood-platelets that are caused by the use of various anticoagulants, and incidentally she has suggested an explanation of the disappearance of platelets in -stored blood. Specially shaped glass bulbs were used which had carefully ground apertures at either side ; these apertures were sealed with coverslips held in place with soft paraffin. Blood was collected in an oiled syringe, mixed with dry anticoagulant in a waxed beaker, and then transferred to the glass bulbs which were
steadily
rotated
a motor. For control, some of the put into a bulb coated on the inside with soft paraffin. The platelets were counted by a standard method before the blood was put into the bulbs and then
blood
by
was
1.
Payling Wright, H. J. Path. Bact. 1941, 53, 255.
platelet
original coagulant used, but still more on the the anticoagulant. Oxalate, heparin,
concentration of chlorazol pink, and chlorazol blue were tried. With a concentration that would just prevent clotting, the platelet count after 80 minutes’ rotation fell to 20-25% of the initial count with all these anticoagulants ; but when concentrations of eight or more times minimal were used the final count in oxalated blood was about 60% of original and about 45% with the other anticoagulants. In the control bulbs there was only a slight fall in the platelet count. When the stained coverslips were examined, the missing platelets were found sticking to the glass, and it was noticed that at the higher anticoagulant concentrations the platelets tended to adhere only to the glass and not to each other. Payling Wright concludes that anticoagulants reduce the stickness of platelets, possibly by reducing fibrin formation on their surfaces. The disappearance of platelets in stored blood is due to their adherence to the walls of the storage bottles’and not to disintegration, for had this happened clotting might well have been expected when the anticoagulant concentration was minimal and the fall of the platelet count large ; but no clotting occurred. This technique can clearly be extended to pathological problems. Are the bloodplatelets less sticky in purpuras’? Can " thrombasthenia " be demonstrated ? Will the answers help, us to decide between the orthodox school who think that the stickiness.of blood-platelets assists the actual plugging of injured blood-vessels and those who hold that they only help to initiate clotting in the shed blood.2 This method might also be used to seek materials, possibly plastics like Perspex, that platelets will not stick to and could be used for the collection of platelet-containing blood.
TOO MUCH OF A GOOD THING NATURE has been none too bountiful with her supplies of the vitamins,.as the widespread incidence of deficiency diseases shows. The possibility of overdosage, therefore, hardly arose before the interference of man led to the detection, isolation and finally synthesis of several of their number. After the synthesis of calciferol by the irradiation of ergosterol, the too energetic exhibition of this substance to infants and children led to several instances of undue calcification and occasional death.34 Hypervitaminosis A has not yet been described in humans, although it can be produced experimentally in rats.9 Overdosage is more readily to be expected with these fat-soluble vitamins, which are not easily elimin ated by the body, than with the water-soluble factors, excess of which is readily excreted in the urine. Nevertheless, a large dose of a water-soluble vitamin might cause for a short time a high concentration in the blood and so possibly lead to untoward symptoms. This, for example, is true of nicotinic acid. Doses of more than 50 mg. by mouth or 10 mg. intravenously may produce flushing and irritation of the skin, and occasionally gastrointestinal symptoms.6 These effects are transitory ; the concentration of the vitamin in the blood rapidly falls as the excess, which is not metabolised or stored, is excreted by the kidneys. Whether large doses of the other water-soluble factors produce undesirable reactions is not certain. It has been suggested that intense treatment with vitamin B1may give rise to symptoms akin to those of herpes zoster-intense irritation of the skin and a burning pain in peripheral nerve areas.7 2. See Lancet, May 3, 1941, p. 574. 3. Hess, A. F., Lewis, J. M., and Rivkin, H. J. Amer. med. Ass. 4. Harris, L. J. Lancet, 1932, 1, 1031. 1930, 94, 1885. 5. Takahashi, Nakamiya, Kawakimi and Kitasato, Sci. Pap. Inst. phys. chem. Res 1925, 3, 81. 6. E.g., Spies, T. D., Bean, W.B. and Stone, R.E. J. Amer. med. A 1938, 111, 584. 7. Steinberg, C. L. Amer. J. digest. Dis. 1938, 5, 680.
.