The Terror of Tuberculosis

by John P. Knud-Hansen

As the story opens, Hardcastle is suffering from phithis, also known as tuberculosis, generally taken to refer to the pulmonary manifestation since it can appear in other parts of the body. The story is set in 1907, by which time the infectious agent, Mycobacterium tuberculosis, had been identified — in 1882 by Dr. Robert Koch, a German physician. Despite this knowledge there would be no effective treatment for TB until the discovery of streptomycin in 1943.

In the meantime, there were multiple attempts at various cures, ranging from moving to “healthier” environments, generally thought to be higher altitudes with lower humidity, to outright quack nostrums. Doyle’s first wife, Touie, had finally passed away the year before this story was set after a 13-year struggle against TB. She and Doyle had moved to a number of places including Egypt and Switzerland in hopes she could be cured, to no avail, although her pulmonary symptoms may have been ameliorated somewhat.

Dr. Koch had discovered a substance called Koch’s Lymph by many and tuberculin by others that was a purified glycerin extract from tubercle bacilli. An injection produced an inflammatory reaction and a subsequent, but temporary, improvement in symptoms that was mistaken for a cure. Demand was very high for a while, and the cost commensurately elevated. However, rigorous follow-up studies demonstrated no evidence of a cure and it was abandoned. It still has some value even today as an intradermal injection to determine if an individual has ever been exposed to TB.

At the time of this story, Dr. Hardcastle has taken himself to a farm in Derbyshire with the hopes that the climate will help him recover from the disease. That this account was unsealed a year later posthumously is an indication of the success of that move. The Terror in the title is a blind cave monster, possibly ursine, which the author initially doubts is real, but comes to believe in before actually seeing it. The locals believe him, but his more educated friends essentially go through the “there, there” routine, some wondering if the TB has now infected his brain. However, the person who found the manuscript spoke to other friends of Hardcastle’s, who unanimously described him as having been “. . . a man of sober and scientific turn of mind, absolutely devoid of any imagination, and most unlikely to invent any abnormal series of events.” Doyle, having lived with Touie’s TB for 13 years, was well-acquainted with the symptoms of TB, and knew that central nervous system manifestations would be rare and certainly not sporadic. Thus it is unlikely he meant to suggest that the monster was a figment of Hardcastle’s imagination.

Some readers have raised the question of differences among socio-economic classes in the treatment of TB. Very likely there was no real difference in effective treatments but since none were effective this was of little importance in terms of public health. Dr. Hardcastle is not receiving tuberculin injections, nor is he taking cod liver oil or any other medication once thought to be effective. He is taking the airs of the country and these alone may have reduced the stress on his lungs, which could have extended his life span if not for the severe stress of his encounter with the Terror of Blue John Gap.


I became a reader of the Canon around high school after reading “Speckled Band” in an anthology of short stories. The idea of any formal Sherlockian organization was unknown to me until 1994, when I heard of and then joined The Denizens of the Bar of Gold on the Eastern Shore of Maryland. It had just been co-founded by Mike Whelan and others. Currently I am assisting Art Renkwitz, BSI, in running that scion. I retired from urology in 2017 and was invested as “This Lascar Scoundrel” in 2019.