He relentlessly questioned and assessed his asthmatic patients. He would have loved to have dissected those who died of the malady, but such an act was forbidden under sentence of death and punishment by the gods.
So he cut into apes, pigs and monkeys instead. He cut open their chests and observed their lungs. He cut into the lungs and traced the air passages. He concluded this was where the vital force of life, the pneuma, enters the body.
He traced vessels from the lungs to the brain. Perhaps this confirmed his assumption, one Hippocrates had alluded to, that asthma was similar to epilepsy. Both asthma also displayed no symptoms between attacks (sporadic), and left no observable traces of disease.
He believed epilepsy was caused by an increased abundance of phlegm in the brain, and this caused seizures. So he concluded asthma was caused by an increased abundance of phlegm in the lungs, and this caused difficulty breathing by blocked air passages.
He also noted a second cause of asthma, and this was tubercles in the lungs. (13, page 1)
In one experiment he severed the medulla spinalis and artificially produced asthma. He used this experiment to prove to his pupils that asthma could be produced artificially. Perhaps later physicians used this experiment as proof that asthma was nervous in origin. (13, page 1)
Asthma historian Mark Jackson said that on Galen's experience he wrote that "if the breathing is rough and noisy it indicates that a large amount of thick and sticky humors in the bronchial tubes of the lungs has accumulated and become annoying because it is difficult to expectorate." (4, page 24)
In this way he is credited by history as being the first to link asthma to the air passages of the lungs, and the first to describe asthma as a disease of obstructed air passages.
As noted, remedies by Galen were meant to restore the balance of the elements and humors. If you sought him out to cure your asthma, he'd probably first recommend a bath, a good diet, and exercise. Once these simple remedies were attempted and failed, only then would he dip into his stock of medicine.
In 1815, Thomas Young said that general remedies prescribed by Galen were copied from the likes of Asclepiades, Musa, Andromachus, Heron, Crito, Menecrates, Archigenes, and Phillipus. Galen mentioned a treatment borrowed from Asclepiades for orthopnia, a common symptoms of asthma, that contained mellepedes, which were supposed to have a diuretic effect (makes you pee). (5, page 145)
Arabic historian Paulus Aegineta said that for asthma Galen prescribed the following (in parenthesis is what modern experts believe would be the effect of the remedy): (6, page 407)
- Squill (alleviates coughing)
- Pepper (stimulates digestive system)
- Wormwood (stimulates digestive system)
- Opoponax (antispasmotic, respiratory decongestant)
- Storax (expectorant)
- Oxymel (expectorant)
- Sulfer (eases allergy symptoms such as sore throat and cough)
- Millepedes (diuretic)(6, page 407)
In 1851, Joseph Bergson said that Galen may even have been among the first to suspect that asthma was nervous in origin. He wrote:
Galen, who made sections of the spinal marrow in different places in living animals, in order to demonstrate to his pupils the influence of it on motions of respiration. (12, page 374)The theories he postulated about asthma, as with all his medical theories, influenced the world for the next 1,800 year. Slowly, through the course of time, a few brave physicians would expound upon his ideas about asthma, and by this means the definition would mature.
References: see the post "120-200 A.D.: Galen becomes world's first physician"