Gas Analysis Apparatus Research Articles

The glucose mobilization rate in hyperthyroidism

The work presented here is a preliminary report of some special investigations we have undertaken during the past twelve months at the Presbyterian Hospital in order to shed more light on the complex problem of hyperthyroidism. The decreased sugar tolerance, so frequently found in this condition, was taken as our point of departure. It occurred to us that the study of the respiratory quotient and the blood sugar at frequent intervals after glucose ingestion might give us a good deal of information as to how cases of Grave's disease utilize carbohydrate. In brief, our procedure was as follows: the metabolism determinations were made with a 90-liter Tissot apparatus, using a Siebe-Gorman mask and Douglas valves. Samples of gas were taken over mercury in the usual way and were analyzed in duplicate in a Haldane gas analysis apparatus and in triplicate if the two analyses did not check satisfactorily. Previous to the use of the Haldane apparatus each day an analysis of outside air was made as a control. The usual technique was observed as to the preparation of the patient—14 to 16 hours fast and absolute rest for thirty to sixty minutes before the start of the determination. After obtaining two basal periods each of ten minutes, blood was taken for a fasting blood sugar. The patient was then given a dose of glucose made as palatable as possible with a small amount of fruit juice. For the most part, a standard dose of 1.75 grams per kilo bodyweight was used. Twenty minutes after the glucose ingestion, the metabolic rate was determined, for a period of ten minutes if possible, and for the next two and a half hours, a determination was made each half hour.

A Gas Analysis Apparatus Accurate to 0·001% mainly designed for Respiratory Exchange Work

A Gas Analysis Apparatus Accurate to 0·001% mainly designed for Respiratory Exchange Work

Time Relations in a Dream

THE following account of a dream which I had last night, and of which I took some notes, may be of interest. The dream commenced by my, as I thought, hearing a drop fall on the laboratory floor; after a time there was another drop. I then realised that mercury was dropping on the floor from a small split in some rubber tubing in a gas-analysis apparatus. As I became more wakeful and seemed to realise that I must get up to deal with the leak, the drops fell more rapidly until they were coming quite fast at the moment when I definitely awoke. I then realised that the dropping of mercury which I heard in my dream was in reality the ticking of the clock in my room.

New Forms of Gas Analysis Apparatus.

New Forms of Gas Analysis Apparatus.

An accurate form of gas analysis apparatus for commercial and other purposes

An accurate form of gas analysis apparatus for commercial and other purposes

THE SOLUBILITY OF AIR IN FATS AND ITS RELATION TO CAISSON DISEASE.

As is now well known, the very varied symptoms produced by rapid decompression from high atmospheric pressures, and popularly known as “ caisson disease” or “ diver’s palsy,” are due to liberation of bubbles of gas—chiefly nitrogen—in the blood and tissues. In the course of a recently published investigation, I found that air is much more soluble in certain oils than in water. Dr. J. S. Haldane pointed out to me the interest of this fact in connection with the causation of caisson disease, and at his suggestion I have repeated and extended my observations. The fats experimented with were olive oil, cod liver oil and lard. In the case of the first two, the solubility was measured at 15° and at 37° C., whilst for lard it was determined at 45° C. In the observations made at room temperature, the oil was shaken violently with air in a bottle for several minutes, and was allowed to stand for 1 to 1½ hours till all the air bubbles had risen to the surface. It was then weighed, and about 40 to 50 grammes of it were sucked up into the vacuous flask of a Geissler’s mercury pump. This flask contained 70 to 100 c. c. of 0·5 per cent, sulphuric acid which had previously been well boiled for an hour so as to get rid of all traces of air. The mixture of oil and water was now boiled for half an hour, the oil breaking up into a very fine emulsion and giving up practically all of its gas in the first few minutes. This gas was pumped off and analysed with Haldane’s gas analysis apparatus. The oil was boiled with dilute acid instead of water, so as to obtain the whole of the carbon dioxide present, both combined and in solution. In determining the solubility at 37°, the oil, previously saturated at room temperature, was warmed to about 38° to 39°, and was shaken vigorously with air for about two minutes. At the end of this time its temperature had fallen to about 36°·5. It was warmed up a second time and the shaking repeated, and was then kept in a water bath at 37° for about half an hour in the case of the cod liver oil, and an hour in the case of the olive oil, these being the times required for all the bubbles of air to rise to the surface. The gaseous content of a weighed amount of the oil was then determined as before. The results obtained are given in the tables. They represent the volumes of gas, reduced to 0° and 760 mm., contained in 100 c. c. of the oil at the temperature recbrded, when saturated with air at a pressure of 760 mm. To calculate these values, it was assumed that the specific gravity of olive oil at 15° is 0·917, and at 37°, 0·902. The specific gravity of cod liver oil, compared with that of water at 15°, was found by direct experiment to be 0·928 at 15°, and 0*914 at 37°.

The solubility of air in fats, and its relation to caisson disease

As is now well known, the very varied symptoms produced by rapid decompression from high atmospheric pressures, and popularly known as “ caisson disease” or “ diver’s palsy,” are due to liberation of bubbles of gas—chiefly nitrogen—in the blood and tissues. In the course of a recently published investigation, I found that air is much more soluble in certain oils than in water. Dr. J. S. Haldane pointed out to me the interest of this fact in connection with the causation of caisson disease, and at his suggestion I have repeated and extended my observations. The fats experimented with were olive oil, cod liver oil and lard. In the case of the first two, the solubility was measured at 15° and at 37° C., whilst for lard it was determined at 45° C. In the observations made at room temperature, the oil was shaken violently with air in a bottle for several minutes, and was allowed to stand for 1 to 1½ hours till all the air bubbles had risen to the surface. It was then weighed, and about 40 to 50 grammes of it were sucked up into the vacuous flask of a Geissler’s mercury pump. This flask contained 70 to 100 c. c. of 0·5 per cent, sulphuric acid which had previously been well boiled for an hour so as to get rid of all traces of air. The mixture of oil and water was now boiled for half an hour, the oil breaking up into a very fine emulsion and giving up practically all of its gas in the first few minutes. This gas was pumped off and analysed with Haldane’s gas analysis apparatus. The oil was boiled with dilute acid instead of water, so as to obtain the whole of the carbon dioxide present, both combined and in solution. In determining the solubility at 37°, the oil, previously saturated at room temperature, was warmed to about 38° to 39°, and was shaken vigorously with air for about two minutes. At the end of this time its temperature had fallen to about 36°·5. It was warmed up a second time and the shaking repeated, and was then kept in a water bath at 37° for about half an hour in the case of the cod liver oil, and an hour in the case of the olive oil, these being the times required for all the bubbles of air to rise to the surface. The gaseous content of a weighed amount of the oil was then determined as before. The results obtained are given in the tables. They represent the volumes of gas, reduced to 0° and 760 mm., contained in 100 c. c. of the oil at the temperature recbrded, when saturated with air at a pressure of 760 mm. To calculate these values, it was assumed that the specific gravity of olive oil at 15° is 0·917, and at 37°, 0·902. The specific gravity of cod liver oil, compared with that of water at 15°, was found by direct experiment to be 0·928 at 15°, and 0*914 at 37°.

A Convenient Form of Gas Analysis Apparatus

In a recent publication1 I described a gas analysis apparatus suitable for rapid and accurate laboratory work. This apparatus is, however, somewhat cumbrous, and cannot easily be conveyed from place to place, as is very often required in investigations relating to questions of hygiene. It also occupies a good deal of working space in a laboratory, as it cannot be moved from its place without a good deal of trouble. On the other hand the already existing forms of portable gas analysis apparatus for technical work are too inaccurate for many of the requirements of work in hygiene and physiology. I have therefore designed an apparatus with a view to meeting these defects as far as possible2.

Deep-Sea Soundings

IN reference to the very interesting article in NATURE for February 22, “American Deep-Sea Soundings,” may I be permitted to make the following remarks:—It is there stated that the water-collecting cylinder is apt to lead to incorrect conclusions in regard to the gaseous ingredients of sea water obtained by its means from great depths, owing to the escape of a portion of the gases when the pressure is relieved by the cylinder being drawn to the surface. As a member of the Porcupine expeditions of 1869 and 1870, I had nearly eight weeks' constant daily experience in the examination of samples of abyssal water thus obtained, and I believe that I was the first to adapt the gas analysis apparatus of the late Prof. W. A. Miller to the exigencies of a laboratory on board ship. The general result of these experiments for 1869 will be found as an appendix in No. 121 of the Proceedings of the Royal Society. My object in writing now is to point out that if there were such an escape of gaseous ingredients as is indicated above, the abyssal water would be so saturated with them at the ordinary atmospheric pressure (i.e. after the sample was removed from the water cylinder in the laboratory), that the least elevation of temperature would be sufficient to cause a further quantity to be given off. This, however, never was the case, since I invariably noticed that there was no appearance of bubbles of gas, until the water had been heated above 120° Fahr., and frequently still hotter. I may add that the only samples of water which appeared saturated with gaseous ingredients were those taken at the surface, after several hours of strong wind. I must confess that after giving a good deal of thought to the subject, and conversing with friends whose knowledge of physics is far greater than mine, who agree with my view of the matter, I am unable to see any reason why we should expect to find any greater quantity of gaseous ingredients in abyssal than in surface water. No doubt, if the excess were there the enormous pressure would retain it, but where is the source of the supply of the supposed excess? I have never seen a satisfactory answer to this question. The solvent is exposed to excessive pressure, but the gases to be dissolved in it are not, unless there is any evolution of gas at those depths. It is probable that this abyssal water was at some point in its circulation near the surface, when an interchange would take place between some of its dissolved carbonic acid and the oxygen of the atmosphere. And it appears to me that it is only when the particles of sea water are near the surface, and exposed to no excess of pressure, that they dissolve their gaseous ingredients, which are afterwards modified in their composition by the animal life on the sea bottom.