762 UNIrED STATES OF AMERICA.

by the pre-eminence of vision. Vision is the sensewhich provides the most delicate form of sensory.discrimination which man, and presumably any.animal, has yet attained.

Although there is strong evidence of representationof complex phenomenon of perception in the peripheralmechanism and lower neural centres in the eye,much remains unexplained. For instance, it isnot known why a presentation which arouses a givenpattern by direct visual fixation arouses the samepattern when it falls upon the peripheral retina,.even in spite of differences of size, intensity, andcolour. A circle remains a circle when viewedobliquely though the retinal image is now an ellipse.In the present state of knowledge the explanationmust be sought from psychological factors, the

physiological bases of which are unknown. One.such is attention upon which the configuration andsignificance of a perceptual pattern must depend.Attention sensitises the formative zone with thexesult that the impulses are correlated into a patternwhich arouses a definite perceptual pattern-apercept of the higher order. On subsequent occasionsthe impact of the excitation arouses a more andmore highly developed pattern as a primary response.and in instinctive reactions this occurs upon thefirst occasion owing to the innate configuration of theformative zone.

Prof. H. E. RoAF reported an experiment whichshowed that there is an overlap in " the common end-point " of the two eyes in the brain.

TEN DISTINCT SKIN SENSE-ORGANS.

Dr.R.S.CREED suggested two points to be elucidated :first, the mechanism of the ten distinct skin sense-

organs. Of these we have merely a slight knowledgeof the pacinian corpuscles-namely, that deforma-

tion is an adequate stimulus to We are still indoubt as to the sensation evoked‘, it is even possiblethat 4"7i s. concerned with reflexes and not with sensa-.. tion at all, since AthQii!8 bodioct are also found in.abdominal viscera. The precise organs for responseto heat and cold are unknown and exhaustive searchoften reveals no nerve-endings. What are the end-

organs of the sense of position ? Secondly, little isknown of the changes that an impulse may undergo.at the many relays in the efferent system. Some

integration occurs below the level of the sensorium.Prof. H. HARTRIDGE criticised the classroom analogy

of the sensory system to that of the telephone, sinceit takes no account of memory.

Sir EDWARD SHARPEY SCHAFER pointed out thatit is hard to accept Head’s dual system for threereasons: First, his own experience from sectionof two cutaneous nerves in his arm does not upholdHead’s work. Secondly, Trotter, from his study ofnumerous cases has obtained diametrically oppositeresults. Thirdly, pain is a sensation of higher ratherthan lower animals, so that the idea that protopathicsensation is more primitive is undermined by fact.

Prof. D. W. BRONK laid stress on the importance ofcorrelating the intensity of the stimulus to the sensa-tion. Prof. Adrian’s work has shown that the

frequency of impulses falls off after repetition of thestimulus. In a comparable way, on the motor side,the discharge of stimuli become more frequent withthe greater call to activity ; this has been observedin the phrenic nerve during asphyxia.

Dr. E. P. POULTON showed tracings taken from amanometer connected to an inflated bag placed in thealimentary canal of patients and healthy individuals.Pain occurred when the gut wall was stretched andit was relieved when the lumen was reduced either by

the muscular contraction of organ or by deflation ’1’îof the bag. If the bag did not yield to the muscularcontraction the pain persisted. His tracings also showedthat stimulation of an area of refined pain altered therhythm and extent of the contraction of the viscus.

Prof. H. H. WOOLLARD said that the nerves of theprotopathic areas showed a characteristic anatomy:a thick fibre with multiform uniform endingsaccompanied by a very fine fibre with a diffuse

ending. These nerves are found in the glans, themammary gland, parietal peritoneum, and in muscles.

Sir CHARLES SHERRrrNGTON said that the timerelations are of great use in the study of the occurrencesbetween initial stimulus and conscious sensation.

Prof. ADRIAN summed up by saying that we arevery ignorant of the confines between physiology andpsychology. It is just assumed that sensations

develop during childhood and that, as we grow up,they are differentiated from the complex mass

received.

UNITED STATES OF AMERICA.

(FROM AN OCCASIONAL CORRESPONDENT.)

THE TYPHUS-LIKE DISEASES.

A PROMISING field of investigation has been foundin the typhus-like diseases of this continent. Theseinclude Brill’s disease, or the endemic typhus of theEastern and Southern States ; Rocky Mountainfever, which now appears to be endemic in the Eastas well as in the Mountain States, and tabardillo, orMexican typhus, which may or may not date fromthe Spanish conquest. Between European typhusand the endemic typhus of Eastern States there hasbeen established complete cross immunity. Epidemio-logical evidence suggests the rat-flea as the sourceof Brill’s disease and the rat as a reservoir of infection.The rat mite (Liponyssus bacoti) must also be con-sidered a possible vector. However, the recent dis-covery of typhus virus present in nature in theflea 1 is of significance when coupled with epidemio-logical evidence.Cross immunity is not found between RockyMountain spotted fever and endemic typhus (Brill’sdisease), but it is well marked between the strainsof spotted fever virus obtained from the RockyMountains and from Eastern States.2 In each casethe vector seems to be a tick. The dog tick (Derma-centor variabilis) is incriminated in the East, and inthe West the wood tick (D. andersoni), which, besidesspotted fever, also carries the virus of tick paralysis,Colorado tick fever, and tularaemia. The rabbit tick

(Hœmaphysalis leporis-palustris) conveys spotted feverfrom rabbit to rabbit, but does not infest man. Itsrole in maintaining a reservoir of infection will be apart of the investigation to be undertaken in thelaboratory in Hamilton, which this year has beenacquired by Congress from the State of Montana forthe U.S. public health service. A total appropriationof$150,000 was made, and half of this will be avail-able for enlargements and improvement of thefacilities. The demand for tick vaccine has beenincreasing ; some 20,000 people have been vaccinatedin the Mountain States during the last four years.For this and for research purposes about 200,000infected ticks are reared each year.

1 Dyer, R. E., Rumreich, A. S., and Badger, L. F.: U.S.Pub. Health Rep., 1931, xlvi., 334; also Kemp, H. A.: Jour.Amer. Med. Assoc., Sept. 12th, p. 775.

2 Dyer, R. E., Rumreich, A. S., and Badger, L. F.: Jour.Amer. Med. Assoc., August 29th, p. 589.

763NOTES FROM INDIA.

Much work remains to be done on all these diseases,and especially on tabardillo. The infectious agenthas recently been found 3 in the brains of rats (Musrattus) in Mexico City. Whether fleas, mites, ticks, orbed-bugs convey the disease from rats to men has notyet been determined. Zinsser favours the bed-bug.He points out that in Vera Cruz, where the climate istropical and ideal for flea life, typhus is quite rare,whereas in Mexico City, 7300 feet higher, fleas haveless congenial environment than the more hardy bed-bug. In Mexico City there are epidemics of typhusevery year. Moreover, he says, the bed-bug will" bite anybody and anything under any circum-stances." With Dr. Castaneda, he has kept the virusof typhus alive by rectal injection and by feedingof bed-bugs on typhus rats. It should be possibleby animal experimentation to discover whether thebed-bug can reconvey infection to the animal itbites. In the last analysis it will be epidemiologicalresearch which determines which vector is of the

greatest practical importance. One waits also forcross immunity experiments with the virus of tabar-dillo against the virus of the other two typhus-likediseases.

NOTES FROM INDIA.

(FROM OUR OWN CORRESPONDENT.)

Health of British Troops.THE Public Health Commissioner tells us 4 that in

a year in which the average strength of British otherranks was 55,628, and that of officers 2395, the ratesper 1000 of admissions to hospital were 609-5 and 415-9,while deaths amounted to 2-84 and 7-10 respectively.This striking difference in the mortality figuresbetween officers and men is accounted for by the I,fact that of the total of 17 deaths of officers, 8 weredue to injury, but it is nevertheless true that over aperiod of ten years the average mortality of officershas exceeded that of other ranks, the figures being5-49 and 3-29 respectively. No particular reason is

assigned for this excess. Thirty or forty years agoit might have been attributed in great part to thedifference in housing. At that time, while the menwere generally housed in fine stone barracks, withgood sanitary arrangements and careful supervisionof the kitchens, it was no uncommon thing to findtheir officers living in thatched bungalows, the floorsof which were made of mud, liberally smeared withcow-dung, while the kitchens and sanitary arrange-ments were often filthy, fly-ridden, and uncared for.No doubt there is still a balance well on the creditside for the men, but the conditions for officers arenow very much improved, and it is to be hoped thereis some other explanation for the discrepancy, suchas that of this year, which evidently exists.

CHIEF CAUSES OF INVALIDITY.

For other ranks the year was a normally healthyone. The principal causes of admission to hospitalwere malaria, local injuries, minor septic diseases,venereal diseases, sandfly fever, tonsillitis, dysentery,and bronchitis, in order of frequency. Of these,malaria, sandfly fever, diarrhoea, dysentery, andtonsillitis all showed a definite increase. There wasa decrease in venereal diseases, which were 206 lessthan in the previous year, at 2552. The total of158 deaths, or 2-84 per 1000 of the strength, compares3 Mooser, H., Castaneda, M. R., and Zinsser, H. : Ibid.,

July 25th, p. 231.4 Annual Report of the Public Health Commissioner with the

Government of India for 1929, Vol. II.

with 2-95 per 1000 in 1928, and 3.34 in 1913. The

most important causes of deaths were local injuries,the enteric group of fevers, and pneumonia. Appendi-citis accounted for 9, drowning for 8, and suicide for 6.It would be interesting to have a comparative state-ment for the last item over a period of years. No-doubt present conditions in India are productive ofconsiderable strain for the Army. The averagenumber constantly sick in hospital was 30-44 per 1000of the strength, as compared with 29-04 in 1928,29-18 in 1927, and 29-68 in 1913. Out-patientsaveraged 19-88 per 1000. The figures for invalidingare much the same as those of the previous year-9-78 per 1000 of the strength, as compared with9-87 for 1928, and 7-49 in 1913. Of the total 544,57 were invalided for tuberculosis, 52 for diseasesof the middle ear, 52 for mental diseases, 36 fordisordered action of the heart, and 28 for epilepsy.

THE REVIVAL OF " P.U.O.’’

The enteric group of fevers shows a considerableincrease at 233, as compared with 197 in the previousyear, though deaths are not a large item in themortality list (19 as contrasted with 18). As theincidence and nature of these fevers amongst Britishtroops is closely related to that amongst Indiantroops, they have been tabulated and analysedtogether. The increase in the former has been

largely due to typhoid, while in the latter it has beendue to both typhoid and paratyphoid A and C

infections. Under the present regulations a case mayonly be diagnosed as typhoid or paratyphoid if theinfecting bacillus has been isolated. Cases in whichthere has only been demonstrated a definite rise inthe curve of agglutination by the Widal test, or whichhave been merely clinically diagnosed enteric, are

classified as " enteric group." It is recognised in aD.M.S. circular of the year that there is still a con-siderable use for the heading " P.U.O.," in spite ofincreased facilities for diagnosis, and this heading,which has sometimes been looked on as a refuge forslackness, seems to have returned to favour. Thecircular justly remarks, after laying stress on thenecessity for accurate diagnosis where possible, thatthere is still, in all probability, a large group offevers which are not recognisable by existing methods,and that these can properly be entered as P.U.O.It is clear that increased interest is all the time beingdisplayed in laboratory investigations, and thissection of the report well repays attention

MALARIA, SMALL-POX, DYSENTERY.

As regards malaria, the admission-rate has fallensteadily for the past five years. During the yearunder review it rose somewhat, but the rise wasalmost entirely due to an outbreak of malignanttertian in the North-West Frontier Province andNorthern Punjab. Plasmoquine was under trial insome of the larger hospitals, and is reported onfavourably. Malaria surveys were carried out during1929 in a number of the most malarious stations, inamplification of similar work done in former years,and operations based on these surveys have beenstarted. Anti-mosquito measures, which in normalyears have proved very effective, apparently failedthis year in checking the onset of epidemic malariain Northern India. Small-pox has been conspicuousby its absence ; only four cases occurred during theyear. This should serve as a useful object lesson tothose who are clamouring for relaxation of vaccinationthroughout India. Dysentery, which accounted for1039 admissions, is still attracting much attention.Material from the stools of 4235 cases reported as