Killick was born on 3 May 1902 in Ilford to Arthur Killick and Henrietta Fanny (née Moulton). She attended Leeds Girls' High School and went on to study at the University of Leeds, earning a BSc with honours in physiology followed by an MB ChB in 1929. She later received an MSc (1937) and DSc (1952) from Leeds.[1]
Killick began investigating respiratory physiology and carbon monoxide poisoning in her first role at Leeds, and this was her primary research interest throughout the rest of her career. In Birmingham, she conducted a series of experiments in which she "gassed herself for science"[1] (as reported by the Birmingham Gazette in 1941) by exposing herself to carbon monoxide in a sealed box at weekly intervals, causing herself to become hypoxic and sometimes lose consciousness. She did, however, demonstrate acclimatisation over time, with her symptoms and blood carbon monoxide levels decreasing with successive sessions over a period of many months. She reported her findings in articles published in 1936 and 1948.[1] She was the first to show that humans and mice acclimatise to carbon monoxide differently due to differences in the respiratory epithelium.[3] Later in her career, she investigated treatments for carbon monoxide poisoning, using different gases to ventilate dogs that were unconscious due to excess carbon monoxide; she showed that a mix of 95% oxygen and 5% carbon dioxide was more effective than air or pure oxygen.[1]
As carbon monoxide is now understood to be a neurotransmitter (see carbon monoxide-releasing molecules and heme oxygenase), Killick made pioneering discoveries pertaining to physiological roles upon recognizing a vasodilatory effect of carbon monoxide on a feline pulmonary arterial vessel in 1951.[4] Similarly, in 1940 Killick recognized heme degradation products (pseudohemoglobin) correlate with continued presence of carbon monoxide in the blood of patients recovering from carbon monoxide poisoning, the observation is a trace origin for endogenous carbon monoxide produced via catabolism of heme by heme oxygenase.[5]