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action, notwithstanding the loss of all the nicotine andtar products, which are the two elements possessingdefinite disinfecting power. The bactericidal sub-stances contained in this decolorised smoke are

soluble in water, one of them being capable of dis-tillation at 100° C. and identical with formaldehyde,the other not capable of distillation was pyrrol, thebactericidal action of which as a component of tobaccosmoke, and hitherto unknown, is important. The dis-infectant action of tobacco smoke is, however, due tothe activity of many elements, among which may beenumerated with certainty tar products, nicotine,formaldehyde, and pyrrol. It may be recalled that,as shown in our own investigations of the subject(THE LANCET, April 6th, 1912), the main constituentsof tobacco smoke are found to be basic in character,and germicides, generally speaking, are of the acidictype-e.g., salicylic acid, benzoic acid, boric acid,- carbolic acid, hypochlorous acid, and so forth. Whetherthis differentiation has any significance is not clear, butthe experiments recorded remind us of the traditionthat during great cholera epidemics those who smokedclay pipes proved immune from the disease, thoughsurrounded by numerous cases.

TUBERCULOSIS OF THE CERVIX.

TUBERCULOSIS of the cervix is a rare condition,- since Chaton in 1908 was able to collect only 87 cases.The first of which a pathological description is givenwas reported by Cornil in 1889, in which Pean per-formed hysterectomy under the impression that thedisease was cancer. Dr. Verdelet and Dr. JosephDaraignez,l of Bordeaux, to whom we are indebted forthis information, relate a case in an unmarried woman,.aged 25, who had suffered for 12 months from profuseleucorrhoea accompanied by loss of weight and profoundasthenia. She had never menstruated. Local examina-tion showed an infantile uterus with a polypus of thecervix surrounded by small ragged ulcers. Althoughsmears did not show any tubercle bacilli, the possi-bility of a tuberculous lesion was considered in view ofthe general condition and the presence of obviouslytuberculous glands in the neck, axillse, and groins, andenlargement of the hilus glands on X ray examination.The polypus was therefore excised and the ulcers.curetted and cauterised. Histological examinationshowed numerous glandular tubules between whichwere typical tuberculous follicles. As there was noevidence of disease of the body of the uterus or theadnexa, it is probable that the infection had beenconveyed from the tuberculous glands by the bloodor lymphatics. In view of the infantile condition ofthe uterus, which might account for the slow progressof the affection, the writers express the hope that thedisease would not spread farther. Should, however, anupward extension take place, hysterectomy would berequired. --

THE DIPPING RESPONSE.

THE imperative necessity of keeping the respiratorypassages clear, and of protecting the organism againstthe introduction into them of liquids or of irritatinggases, has led to interesting protective mechanism.One method of defence is the closure of the inlets,which can be accomplished by a reflex inhibitory arrestof the respiratory movements-prevention being betterthan cure-and the other is a forced expiratory blast,a vigorous cough or sneeze, to remove the offendingentrant. The classic example of the latter is the actionof the superior laryngeal nerve when food " goes thewrong way." Before the modern term defensive or

protective was invented the old surgeons used to callthe reflex the sentinel of the larynx. The inhibitoryreflex respiratory mechanisms are particularly interest-ing in diving birds or in animals that may naturallyhave to sojourn for a long time under water. ProfessorRichet, of Paris, used to show in his lectures a veryimpressive experiment; he plunged a duck underwater and asked his audience to determine by their

1 Journal de Médecine de Bordeaux, Sept. 25th, 1920.

watches the time the duck could be submerged with-out breathing. The time is shortened by atropine,probably because of the acceleration of the heart beat.Many years ago Professor Fredericq, of Liege, recordedthe arrest of breathing in ducks when he poured wateron the nostrils, the mouth being kept open; MissFrances Huxley some years later re-investigated thesame phenomenon and found that as soon as watercame in contact with the nasal mucous membrane areflex apnaea was induced. Obstruction of the nostrilsdoes not interrupt breathing; the animal still breathesthrough the mouth. Even when the mouth is filledwith water and the nostrils closed no inhibition occurs.The same negative result obtains if the nostrilsare closed with the ftngers and the animal sub-

merged, but as soon as the finger pressure isremoved apnoea is observed. Experiments withpigeons give the same results, and an analogousdipping reflex has been observed in dogs. SwaleVincent and A. T. Cameron, in the Journat of! comparative Neurology, 1920, have extended theseobservations and made others. White rats, if plungedinto water at body temperature, cease to breathe assoon as the nostrils come in contact with the water, andsince this phenomenon occurs also in narcotised animalsit is not a voluntary cessation of the respiratory move-ments. Mechanical or chemical obstruction of thenostrils is without effect. When the vapour of chloro-form or ammonia reaches the nostrils of a rabbit itcloses its nostrils, ceases to breathe, and there issimultaneous reflex arrest of the beat of the heart. Isthis an adaptation to its burrowing habits? Axenfeldseveral years ago investigated the reflex arrest of therespiratory movements in the submerged frog as soonas its nostrils touch the water, and came to the con-clusion that the nasal mucous membrane of the frog is

specifically stimulated by air and water, contact withair discharging respiratory movements, while watercontact brings about their arrest. If the nasal mucousmembrane is injured by the application of 20 per cent.acetic acid and the frog placed under water, there is nointerruption of the respiratory movements, and themouth fllls with water. This inhibitory dipping reflexseems to be more marked in the frog than in otheranimals. A frog may live for several weeks underwater without, during this time, making any respiratorymovements-the respiratory exchanges through its sldnsufficing for its modest needs. It would seem, therefore,that in all vertebrates there is a reflex mechanismwhich can arrest the respiratory movements when thehead of the animal is dipped under water. The

receptors for this reflex lie probably in the epitheliumof the nasal mucous membrane.

THE NAVAL MEDICAL SERVICE AS A CAREERIN AMERICA.

THE Surgeon-General of the United States Navy, or,as we would say, the Medical Director-General, AdmiralW. C. Braisted, who is also President Wilson’s personalphysician, contributes to the Navy Number of theMilitary Surgeon an article asking temporary officers ofthe Medical Corps of the United States Navy to join thepermanent service. The precedence they will have isstill to be arranged, and it would seem to be assumedthat they will get the ordinary pay of their rank, thoughthis is nowhere stated. But the interest of the articlelies in the Surgeon-General’s published exposition ofthe advantages to a young doctor of service in thenavy. The services of young doctors in the UnitedStates are at present so much in demand, theimmediate rewards of practice are so great, thatservice in the navy makes little immediate appeal.The people of the United States have recentlybecome so wealthy that those who formerly wouldhave joined medical clubs have now their privatephysicians, and practice has become unexpectedlyremunerative. But it is a practice without largepromise for the future, so the Surgeon-General appealsto those with greater ambition to remember that, evenif service in the navy offers a relatively modestcompetency. it gives a dignified and respectable