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THERMOPHILIC BACTERIA IN MILK.
1249 relation of temperature and pulse-rate in disease. After illustrating the close correspondence between
from 420to 70’ C. and an optimal growth temperature of 50’to 60 C., and facultative therm ophiles which grow best at 37° C. or other lower temperatures, but which can also grow at 55° C. Many of the common sporing aerobes, such as B. mesentericus or B. subtilis, can accommodate their growth to the higher temperature. The author introduces a third group, the thermotolerant bacilli, which grow best at the higher temperatures but which can grow at blood heat. All the strains studied from the Baltimore milk-supplies were aerobic spore-bearing bacilli. Their liability to cause decomposition changes in foods depends on the extent to which they possess proteolytic and fermentative properties. While most can liquefy gelatin and some produce acid from sugars, none caused gaseous fermentation and their proteolytic powers were absent or slight. They are not likely to be a cause of decomposition changes in canned foods or to alter milk, although some of the isolated strains grown in milk at 55° C. in pure culture were able to coagulate it. They have some significance in connexion with pasteurisation, since they survive this treatment. The obligate thermophiles were found not to multiply in milk at 62° C. On the other hand, the thermotolerant types multiplied greatly at this high temperature and particularly at 55° C. These strains, therefore, may cause trouble to pasteurising plants by multiplying during the process and giving the milk a high count. They may cause pin-point colonies at 37’C. Their existence is one of the causes of high counts after pasteurisation, a condition which occurs from time to time. Sweetened and unsweetened canned milk tins were investigated but no true thermophiles were found in them. The only organisms which developed at 55° C. were bacilli of the mesentericussubtilis group, This is in accord with the findings of J. Weinzirl in U.S.A., although W. G. Savage and R. F. Hunwicke in England found obligate thermophiles in sweetened milk in a number of instances and one strain in unsweetened milk. These strains were, however, unable to initiate unsoundness and were regarded as of no practical importance by their discoverers. The only exception at present to the view that thermophilic bacteria are not a cause of decomposition changes in foodstuffs is the observation by E. J. Cameron and J. R. Esty (1926) of unsoundness changes from this cause in canned corn and other vegetables, giving rise to what they call " flat sour
pulse-rate and the temperature chart when both plotted in acute infectious diseases, he emphasises the clinical significance which attaches to deviations from this rule. It is assuredly true that though the clinical thermometer supplies a means of graphically recording the body’s response to infection with a relatively small margin of error on the part of the observer, the pulse-rate will frequently give warning of grave complications, especially of a myocardial nature, which may be overlooked if the temperature chart alone is considered. During the influenza epidemic of 1918, when cases were admitted to military hospitals in thousands daily, it was a common experience that selection for immediate special treatment of those patients who exhibited marked pyrexia was a very poor guide to the real gravity of the cases, whereas an experienced nurse could, by observation I of the pulse-rate, pick out the more serious cases with ’, In surgical practice this a high degree of accuracy. aspect of clinical observation has long been recognised, a rising pulse with a falling temperature being, as Prof. Carmalt-Jones points out, of the gravest significance. In some hospitals it has been found that in cases of suspected spreading peritonitis the surest guide during the hours immediately following admission is to keep a record of the pulse-rate every half hour, without reference to the temperature, and on this indication alone early and successful operation has been performed at a time when the other clinical signs remained doubtful. In more chronic pyrexial conditions it is as a guide to the condition of the myocardium that a pulse chart becomes most useful. In cases of good resistance in which recovery occurs without damage to the heart muscle, the pulse-rate falls with the temperature, and any delay in the fall of the pulse-rate relative to the temperature is in proportion to the myocardial damage done. It remains to be recognised that pulse-rate records require more care on the part of the observer than do similar records of temperature. Even a junior nurse will look twice at her thermometer, and possibly take the patient’s temperature again, when the reading is in any way surprising ; but we have again and again been struck by the unwondering calmness with which a normal pulse-rate is recorded by an otherwise skilful nurse in cases of heart failure, where only a proportion of ventricular pulsations is in spoilage. reality reaching her fingers over the radial artery. This is a point which seems to escape proper comment A COMPREHENSIVE STUDY OF POSTURE. in many teaching hospitals, and it is one which Prof. Carmalt-Jones might well have stressed in his THE subject of correct posture and of departures paper. In continental hospitals the daily volume of from it and their treatment has received far more the
are
_____
urine secreted is sometimes used as the most accurate index of the cardiac function ; again, accuracy and simplicity of recording are the criteria which must
decide the utility of the method, and again it must be admitted that, like pulse charts, urine charts are not as easv to obtain at the bedside.
as are
THERMOPHILIC
the
more
familiar records
_____
BACTERIA IN
MILK.
Knowledge or bacteriology extentis we are the range for bacterial growth, both in relation to temperature and to other environmental conditions, greater than was once supposed possible. There are, for example, halophilic bacteria which flourish in solutions of salt, inimical for most bacteria. Another interesting group is that of the thermophilic bacteria whose optimal growth temperature is well above normal body temperature and is generally in the neighbourhood of 55° C. While this group is of no direct significance in human pathology, it is of some importance in commercial processes, particularly in1 In a recent paper relation to canned foodstuffs. Miss Eckford discusses the significance of thermophilic bacteria in milk. A distinction must be drawn between true or obligate thermophiles with a range of growth As our
finding
1 M. O. Eckford: Amer. Jour. of Hygiene, 1927, vii., 201.
attention in the United States of America than in this country, or indeed, in Europe generally. In the U.S. Public Health Reports this subject has been recently reviewed1 boy Dr. Louis Schwartz, who gives a bibliographical list of 154 publications, beginning with the quaint " Anthropometamorphosis " by Tohn Bulwer, of 1650, but not including some articles on the subject which have been published in the last year or two in our pages and elsewhere in this country. Some orthopsedic surgeons in the United States have attributed far-reaching pathological results to faulty habits of standing and sitting, and the existence of an American Posture League testifies to the place such matters occupy in the public attention. In this country faulty posture is regarded as the result rather than as the cause of illness, and due to a general weakness and lack of postural tone in the skeletal muscles. Too much, perhaps, has been made by some writers of the contrast between the spinal curves of the quadrupeds and anthropoids on the one hand and of man on the other. In a paper published in 1886 D..T. Cunningham showed2 that 1 A Résumé with Comments of the Available Literature relating to Posture, by Louis Schwartz, Surgeon, United States Public Health Service, Washington, May 6th, 1927. 2 The Lumbar Curves in Man and Apes, by D. J. Cunningham. A paper read before the Dublin Academy and abstracted in Nature, 1886, xxxiii., 378.
from 420to 70’ C. and an optimal growth temperature of 50’to 60 C., and facultative therm ophiles which grow best at 37° C. or other lower temperatures, but which can also grow at 55° C. Many of the common sporing aerobes, such as B. mesentericus or B. subtilis, can accommodate their growth to the higher temperature. The author introduces a third group, the thermotolerant bacilli, which grow best at the higher temperatures but which can grow at blood heat. All the strains studied from the Baltimore milk-supplies were aerobic spore-bearing bacilli. Their liability to cause decomposition changes in foods depends on the extent to which they possess proteolytic and fermentative properties. While most can liquefy gelatin and some produce acid from sugars, none caused gaseous fermentation and their proteolytic powers were absent or slight. They are not likely to be a cause of decomposition changes in canned foods or to alter milk, although some of the isolated strains grown in milk at 55° C. in pure culture were able to coagulate it. They have some significance in connexion with pasteurisation, since they survive this treatment. The obligate thermophiles were found not to multiply in milk at 62° C. On the other hand, the thermotolerant types multiplied greatly at this high temperature and particularly at 55° C. These strains, therefore, may cause trouble to pasteurising plants by multiplying during the process and giving the milk a high count. They may cause pin-point colonies at 37’C. Their existence is one of the causes of high counts after pasteurisation, a condition which occurs from time to time. Sweetened and unsweetened canned milk tins were investigated but no true thermophiles were found in them. The only organisms which developed at 55° C. were bacilli of the mesentericussubtilis group, This is in accord with the findings of J. Weinzirl in U.S.A., although W. G. Savage and R. F. Hunwicke in England found obligate thermophiles in sweetened milk in a number of instances and one strain in unsweetened milk. These strains were, however, unable to initiate unsoundness and were regarded as of no practical importance by their discoverers. The only exception at present to the view that thermophilic bacteria are not a cause of decomposition changes in foodstuffs is the observation by E. J. Cameron and J. R. Esty (1926) of unsoundness changes from this cause in canned corn and other vegetables, giving rise to what they call " flat sour
pulse-rate and the temperature chart when both plotted in acute infectious diseases, he emphasises the clinical significance which attaches to deviations from this rule. It is assuredly true that though the clinical thermometer supplies a means of graphically recording the body’s response to infection with a relatively small margin of error on the part of the observer, the pulse-rate will frequently give warning of grave complications, especially of a myocardial nature, which may be overlooked if the temperature chart alone is considered. During the influenza epidemic of 1918, when cases were admitted to military hospitals in thousands daily, it was a common experience that selection for immediate special treatment of those patients who exhibited marked pyrexia was a very poor guide to the real gravity of the cases, whereas an experienced nurse could, by observation I of the pulse-rate, pick out the more serious cases with ’, In surgical practice this a high degree of accuracy. aspect of clinical observation has long been recognised, a rising pulse with a falling temperature being, as Prof. Carmalt-Jones points out, of the gravest significance. In some hospitals it has been found that in cases of suspected spreading peritonitis the surest guide during the hours immediately following admission is to keep a record of the pulse-rate every half hour, without reference to the temperature, and on this indication alone early and successful operation has been performed at a time when the other clinical signs remained doubtful. In more chronic pyrexial conditions it is as a guide to the condition of the myocardium that a pulse chart becomes most useful. In cases of good resistance in which recovery occurs without damage to the heart muscle, the pulse-rate falls with the temperature, and any delay in the fall of the pulse-rate relative to the temperature is in proportion to the myocardial damage done. It remains to be recognised that pulse-rate records require more care on the part of the observer than do similar records of temperature. Even a junior nurse will look twice at her thermometer, and possibly take the patient’s temperature again, when the reading is in any way surprising ; but we have again and again been struck by the unwondering calmness with which a normal pulse-rate is recorded by an otherwise skilful nurse in cases of heart failure, where only a proportion of ventricular pulsations is in spoilage. reality reaching her fingers over the radial artery. This is a point which seems to escape proper comment A COMPREHENSIVE STUDY OF POSTURE. in many teaching hospitals, and it is one which Prof. Carmalt-Jones might well have stressed in his THE subject of correct posture and of departures paper. In continental hospitals the daily volume of from it and their treatment has received far more the
are
_____
urine secreted is sometimes used as the most accurate index of the cardiac function ; again, accuracy and simplicity of recording are the criteria which must
decide the utility of the method, and again it must be admitted that, like pulse charts, urine charts are not as easv to obtain at the bedside.
as are
THERMOPHILIC
the
more
familiar records
_____
BACTERIA IN
MILK.
Knowledge or bacteriology extentis we are the range for bacterial growth, both in relation to temperature and to other environmental conditions, greater than was once supposed possible. There are, for example, halophilic bacteria which flourish in solutions of salt, inimical for most bacteria. Another interesting group is that of the thermophilic bacteria whose optimal growth temperature is well above normal body temperature and is generally in the neighbourhood of 55° C. While this group is of no direct significance in human pathology, it is of some importance in commercial processes, particularly in1 In a recent paper relation to canned foodstuffs. Miss Eckford discusses the significance of thermophilic bacteria in milk. A distinction must be drawn between true or obligate thermophiles with a range of growth As our
finding
1 M. O. Eckford: Amer. Jour. of Hygiene, 1927, vii., 201.
attention in the United States of America than in this country, or indeed, in Europe generally. In the U.S. Public Health Reports this subject has been recently reviewed1 boy Dr. Louis Schwartz, who gives a bibliographical list of 154 publications, beginning with the quaint " Anthropometamorphosis " by Tohn Bulwer, of 1650, but not including some articles on the subject which have been published in the last year or two in our pages and elsewhere in this country. Some orthopsedic surgeons in the United States have attributed far-reaching pathological results to faulty habits of standing and sitting, and the existence of an American Posture League testifies to the place such matters occupy in the public attention. In this country faulty posture is regarded as the result rather than as the cause of illness, and due to a general weakness and lack of postural tone in the skeletal muscles. Too much, perhaps, has been made by some writers of the contrast between the spinal curves of the quadrupeds and anthropoids on the one hand and of man on the other. In a paper published in 1886 D..T. Cunningham showed2 that 1 A Résumé with Comments of the Available Literature relating to Posture, by Louis Schwartz, Surgeon, United States Public Health Service, Washington, May 6th, 1927. 2 The Lumbar Curves in Man and Apes, by D. J. Cunningham. A paper read before the Dublin Academy and abstracted in Nature, 1886, xxxiii., 378.