This section is from the book "Materia Medica And Therapeutics Inorganic Substances", by Charles D. F. Phillips. Also available from Amazon: Materia medica and therapeutics.
In the experiments of Ackermann, the number of respirations increased in direct relation with the increase in the pulse-rate, but, under the continued influence of the drug, independently of irritant effects, and of any preventing lung-disorder, the rate of respiration is slowed. It may be so by as much as half or two-thirds the normal rate, so that only six respirations occur per minute, and this without general distress or impairment of other functions (Trousseau).
After poisonous doses, the breathing is very irregular, at one time hurried, short, and painful, at another, extremely slow, with labored and forcible inspiration and expiration: this is due in part to paralysis of the heart and other muscles, in part to impairment of reflex sensibility and to altered conditions of the blood. After death in such cases, Majendie, finding the lungs partially congested and hepatized, concluded that the action of antimony was specially exerted on these organs, and Mayerhofer certainly proved its elimination by their mucous membrane: ecchymo-ses and emphysema are found when the act of breathing has been very labored.
The effect of the drug upon the excretion of carbonic acid has been differently stated: some observers report it lessened in amount (Coze, Mialhe, Rabuteau), but recent writers (Ringer, Bartholow), express an exactly opposite opinion, though neither gives his original authority (v. p. 283). Further accurate observations upon this point are admittedly wanting, but having regard to the sedative effects of sufficient doses, independently of inflammatory action, the former statement seems to me more in accordance with known facts. That arsenic lessens the excretion of carbonic acid is now recognized, and though Gubler holds that we do not know enough of arsenical action to make the analogy of scientific value, I should hesitate before ascribing to so closely an allied drug as antimony, a directly opposite effect in this important particular.