Spirometer, W.E. Bowman’s, 1863

Spirometer_W_E_Bowman_1863

From: The Half-yearly Abstract of the Medical Sciences: Being a Digest of British and Continental Medicine, and of the Progress of Medicine and the Collateral Sciences, Volume 38, 1864, page 132.  Original article by W. E. Bowman from the Canada Lancet, June 15, 1863.

“A cheap spirometer may readily be made from two tin vessels similar to shape of the ones figured in the accompanying woodcut; the one should be 20 inches long and 6 inches in diameter and the other 18 inches long and 5 inches in diameter.  The latter may be graduated into spaces of 8 cubic inches by means of our ordinary gallon measure, which is the old wine measure of Great Britain, and the one that is adopted by the United States Pharmacopaeia; it consists, as everybody knows, of 8 pints of 16 ounces each, the ounce meauring 1.8 cubic inches.

“Having placed the smaller vessel perfectly upright, measure into it a gallon of water, less half an ounce, and with a rule ascertain the precise distance from the surface of the liquid to the brim of the vessel, then placing this measure outside the tin, mark the height of the water as 230 cubic inches.  In a similar manner with half a gallon and 10-1/4 fluid ounces mark 134 cubic inches.

“Next, divide the space between these two marks into 12 equal parts, which will measure 8 cubic inches each and with the compasses continue the graduation upwards and downwards, placing the figures on the inverted vessel as here shown.  If its diameter be everywhere alike, the measure must be correct; its accuracy however may be readily tested by the annexed subdivisions of the same measure.  The pulleys and counterpoise may now be adjusted to the graduated tin.

“Next fill the larger vessel with water so that the smaller may be just covered when inserted as low as possible into it, and mark the height of the water on the inside of the tin. Then raise the small one gently until the 174 cubic inch line appears even with the surface of the water and make a second mark of its level.  Finally, put the third graduation on the large tin when the smaller is raised completely out of it.

“Lastly, affix 2 or 3 feet of flexible tubing and a mouthpiece to the top of the small tin and the spirometer will be ready for use.”

Spirometry, 1921

Spirometry_1921

From: The cult of the sound body. Apparatus employed in modern physiological laboratories to test physical development. By T.V. Davidson.  Scientific American Monthly.  Jan 1921, page 34.

“To discover the amount of air taken into the lungs during a deep inspiration, a very simple spirometer is used at Joinville.  It consists of a bell glass balanced by a counter-weight and immersed in a cylinder three quarters full of water.  The subject exhales the air through a rubber tube with a glass mouthpiece, which runs to the lower tubulur of the spirometric vessel.  The section of this tube is exactly equal to that of the trachea so that there will be no resistance to the air proceeding from the lungs of the subject and no alteration of the respiratory rhythm.  The air exhaled causes the internal pressure to be increased and the amount of the increase is shown on a manometer.  Furthermore, if care is taken to graduate the manometer beforehand by injecting exactly 1, 2, 3, 4, 5, etc, liters of air and marking the corresponding level of water for each, the volume of air injected can be read off at once.”

Brown’s Spiroscope, 1866

Spiroscope_A_G_Brown_1866

From: The Science and practice of medicine, Volume 2, by William Aitken, 1866, page 553.  “Mr. A. Gardiner Brown’s spiroscope  is a new and efficient instrument for ascertaining the breathing capacity.  It is a wet meter, 6-1/2 inches square, having a dial with two registers, revolving from left to right, marking in a complete revolution 100 and 1000 cubic inches respectively, and a few feet of vulcanized India-rubber tubing to breathe through.  Its advantages are facility of management, compactness, portability, security of contained fluid and it may be used several times by the same person without readjustment. The air is measured at its initial temperature.  The patient should be taught to practice a powerful inhalation, and as complete an expiration as possible, before noting the mean numbers registered in several trials.  It should be placed at a convenient height for a person sitting or standing.”

Spirometer, Denison’s, 1890

Spirometer_Denisons_1890

Invented by Charles Denison.  From: The Sanitarian. Volume 25, 1890, page 408.  “The spirometer I here show you is of my own experimenting, and I will trust it will commend itself to you as a faithful measurer of vital capacity.  When full it is a hollow cylinder, 11.28 inches in diameter, standing on end, the two ends being closed, and the sides made of one piece of light, impervious cloth.  The structure is so light as to give little or no resistance to the expired breath.  That resistance when desired, however, is intended to be used and measured by weights placed on top of the cylinder, or by a manometer attached, so as to determine the expelling force, in pounds pressure, that each individual may have.”

The diverse, quirky and mostly forgotten history of Pulmonary Function testing