Category Archives: Douglas Bag

Douglas Bag Box, Fenyves & Gut, circa 1970

From a sales brochure kindly provided by Emanuele Isnardi.  The entire sales brochure can be downloaded here.

“Construction: A transparent plastic box on castors houses two bags containing a maximum of 100 litres each for the inspiratory and expiratory air respectively. A valve system connects the bags to a pneumotachograph which measures the inspiratory and expiratory air. A three-way stopcock makes it possible to let the patient breathe ambient air or air from the bag according to choice. The expirate can be collected in the expiratory bag or released to the atmosphere. Device for filling and fan for deflating the bags. The gas concentration can be measured in the bags and continually monitored at the mouth. Additional equipment: gas analyser, depending on test objectives (see under A), multi-channel compensated direct recorder (see under R), computer for direct MV determination.”

Douglas Bag, Basal Metabolism, Sheep, 1964


From “The Energy Exchange of Ruminants” a PhD thesis paper by John Patrick Joyce for the University of Glasgow, 1964, page 28.

“Photograph of outdoor experimental site demonstrating the collection of sheep by when wearing a face mask.”

“A large pit 9 ft x 4 ft x 1 ft 6 inches was dug just in front of the skeleton framework and was lined with wood. This pit acted as a guard for two large Douglas bags when they were being filled by the animal and prevented them from blowing away. Placing the Douglas bags below ground level also ensured they did not act as a wind shelter for sheep, especially when the bags were filled with exhaled air.”