ANNOTATIONS

BIOLOGICAL EFFECTS OF X RAYS.

IN a noteworthy contribution Prof. Sidney Russand his co-workers record the results of experiments,carried out at the Middlesex Hospital over a periodof three years upon the cat and the rabbit. X raysof two different groups of wave-length were usedcorresponding to voltages of 150,000 and 230,000respectively. The minimum dose of radiation

necessary to produce the death of the animal wasdetermined for each type of radiation, the wholeanimal being exposed. It was found that the minimumlethal dose of the morepenetrating radiation was lessthan that of the other type in the ratio of 1 to 2-8.The tissue changes produced were most marked in,small intestine, stomach, liver, spleen, respiratorytract, and white blood cells, although destructivechanges could be produced in any tissue by the.administration of sufficiently large doses of radiation.In the small intestine there was widespread destruction,of epithelium with petechial and even larger hoemor-rhages ; infection occurring at a later stage appearedto be secondary to the destructive effects. Similar.changes were found in the stomach. The largeintestine was more resistant. In the liver, congestion.and fatty infiltration were produced, with patches ofnecrosis. In the lungs changes were found in the- epithelium of the trachea and larger bronchi, withpatchy areas of haemorrhagic and oedematous infiltra-tion of the alveoli ; at later stages endothelialproliferation was observed in the alveolar walls andareas of fibrosis. When, however, the lungs alonewere irradiated they were found to be resistant toradiation, the changes described being due in theauthors’ view to the occurrence of infection. Inthe blood the effects were marked diminution in the1ymphocyte content, followed later by diminutionof the polymorphonuclear cells; indeed, in some of the.experiments the leucocytes almost disappeared fromthe blood for a time. Little or no effect was observed.on the platelets.

In some of the experiments localised regions onlywere exposed, and it was found that the typical changesin the abdominal organs were only produced when-these were directly irradiated. Bacteria were fre-

quently found in the blood at a late stage. In the.authors’ opinion infection plays an important rolein the production of tissue changes, entering theblood stream, it is believed, through the damagedintestinal wall. They refer to work of Cramer,Drew, and Mottram, in which the entrance ofbacteria into the circulation was ascribed to thrombo-

penia produced by the rays-an effect not observedin the present experiments. But Cramer andhis colleagues later inclined to the viewthat the thrombopenia was secondary, and thatinfection arose from the damaging effect upon thetissues. After large doses of radiation a state ofcachexia was produced in the animals somewhatresembling the clinical condition known as "X raysickness." In view of the fact that histamine or asimilar substance is known to be liberated by tissuesdamaged by X rays, experiments were undertakento determine if the absorption of such a substance

Imight be responsible for the production of this

1 The Physiological and Cytological Effects of PenetratingX Rays upon the Cat and the Rabbit. By S. Russ, SamsonWright, H. A. Bulman, and L. H. Clark. Reprint from Pro-ceedings of the Royal Society of Medicine, Section of Electro-Therapeutics, Oct., 1930, pp. 43-60.

condition. It was found that the effects of histamineinjections did not bear any great similarity to X ray

; cachexia. An interesting feature of the research from, the clinical point of view was the investigation of

the effects of liver feeding on the development of theX ray anaeemia. Little or no influence upon theanaemia was detected, but in the animals to which liverhad been administered there was an apparent increasein the sensitivity of the liver itself to the radiations.In all these animals more extensive destructivechanges were observed in the liver as a result of theirradiation than in non-liver-fed animals with similardoses. This observation should lead to caution inthe administration of liver extract in the hope of

benefiting the anaemia produced by clinical irradiation.The authors point out that inferences drawn from

the results of-experiments on lower animals may or maynot be applicable to the human subject, and it is tobe noted that the doses of radiation which theyemployed were relatively much greater than thoseapplied in clinical work. Certain of the resultshowever, have their clinical implications. Mostimportant, perhaps, is the occurrence of septicaemiaafter irradiation of the abdomen, more particularlyin view of the fact that mild intestinal lesions are notinfrequently produced clinically in the treatment ofmalignant disease in the abdomen with heavy doses ofradiation. Moreover, the fibrosis of the lungswhich they describe agrees with the well-knownclinical observations of Finzi and of Wintz ; if, asthe authors believe, this condition is due to infectionattempts might be made to combat it on appropriatelines. Another observation which may prove to be ofpossible clinical importance is the fact that recoverymay appear in the leucocyte count after almost

complete disappearance of leucocytes from the blood.Nothing is known at present clinically as to the pointat which an X ray leucopenia becomes dangerous.Finally, the authors suggest that further study mightbe undertaken of the effects of different diets duringX ray treatment in relation to the occurrence of X raysickness. Certain differences in the general effectsbetween the cat and the rabbit might be due to thewidely differing diets of these animals.

ROAD ACCIDENTS IN DENMARK.

! ONE of the measures which is assuredly calculatedin the long run to check the rising incidence of roadaccidents is an international pooling of experience-a comparison of the various means adopted in thedifferent countries to reduce this evil to a minimum.It was, therefore, a most opportune study whichDr. F. Svendsen, of the Danish Red Cross Society,presented in October to the fourteenth InternationalRed Cross Conference held in Brussels. Afterbriefly reviewing the statistics for the United Statesand showing that the deaths from road accidentsin 1929 in this country were nine times more numerousthan those in 1911, Dr. Svendsen gave the followingstatistics for Denmark for the first six months of1930. __ . _._ _

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It should be noted that these figures deal only withaccidents brought to the attention of the police, and