ls]olels R Zz B a ve SE ee aE a) | | Volume underestimated M 2 Tl 1 490-990 lok +20 1 |1(31.2) 510 M 4 |1(48.6) a) alt 210-525 i) F +15 1 1 410 2| M +10 2 a a 600-685 M 6 D1 all a tlk 287-1000 ile ee 1 a es 1 1 55 22 |18M 17 |3 a} 3) ai ai alal | 4 | 3F 1G Volume as estimated gs | M 6 |1(37.8) | 1 9 | 2 350-790 Bal 8 Fy EA) 5 Dol | et 290-400 TaB to — 2! 3 9} | 1(41.5) 15-105 16 | 8M 14 1 1 2| 216 | 2 | | 5F | | | | 3B | | DETERMINATION OF SIZE OF HEART BY X-RAYS 469 TABLE 17—Continued Volume overestimated M 6 1 ili 1| 2(1-30) 300-810 1 F il 1 510 I B — 5 1 1 16 6 M 6 |1(63.0) wy) aut a 2 320-700 1 F —10 475 4 M 4 1} 3(25, 31, 33.5) 390-1155 1 B —15 1 1(36.7) 75 2 M 2 2(21.8, 34.2) 560-600 1 F —20 al 1 290 24 |19M eee Sal eS 31 e2, 5} 9 3F 2B Weight underestimated! Weight overestimated 53| 5 |3j4l3 |e 7 5 12 ___. _—_— — SS = 15 30 Weight correctly estimated 8 determined for each heart. The hearts were then grouped according to the extent of divergence of observed from calculated volume. Hearts showing a divergence of 23 per cent or less are classed together. The others are classed to the nearest 5, 10, 15 or 20 per cent + or —. Markedly distorted hearts have been excluded but no attempt has been made to select hearts that conform to theory. For the sake of comparison the divergence of observed heart weight from the heart weight calculated from silhouette area is likewise given. This table shows that of the 62 hearts included in the study the volume was correctly calculated from the area to within 23 per cent in 16 cases, to within the nearest 5 per cent + or — in 36 cases and to within 10 per cent (the nearest 10 per cent + or —) in 45 cases. It is probable that greater accuracy can be obtained in estimating heart volume from silhouette area in 470 Cc. R. BARDEEN the living than in the dead since the condition of the heart with relation to the distention of its chambers is more uniform in the living. We believe that the formula given above enables one to calculate diastolic volume from silhouette area to within 5 per cent of the volume in diastole in the majority of instances in the living. In cadavers there is a tendency to underestimate volume from silhouette area when the heart is contracted; to overesti- mate volume when the heart is more distended than is normal in diastole. Whether or not this is true in the living we have no means of ascertaining at present. If we take the heart weight considered standard for a person of a given body weight as de- scribed in Section C, p. 449—and given in tables A and B, and the silhouette area considered standard for a given body weight as described in Section A, p. 431, and given in tables A and B we see that there is a constant relation between silhouette area and heart weight if each is assumed to bear a constant relation to body weight. We may express this relation by the formula: sy area” < 0.0055 = heart weight. The area is here assumed to be the area in square centimeters of the heart silhouette in diastole while sitting at rest and the heart weight that of the whole heart in grams. If the heart is more contracted than is normal in diastole when the body is sitting at rest the weight of the heart in relation to the silhouette area is increased. If the heart is more dilated than is normal for this position the weight of the heart in relation to the sil- houette area is decreased. We thus have a method of deter- mining in a more or less rough way whether or not a heart in the cadaver is more or is less dilated than is normal in diastole when the body is at rest in the living. In table 17 the percentage of divergence of the observed from the heart weight estimated from silhouette area is given for 53 of the 62 bodies in which the relation of silhouette area to volume was studied. From this table it may be seen that of the 17 hearts whose volume was un- derestimated from the shadow area, ten were underestimated from the standpoint of weight and four overestimated. This DETERMINATION OF SIZE OF HEART BY X-RAYS A471 would indicate that there is a tendency to underestimate volume from silhouette area when the heart is contracted. On the other hand of the 22 bodies in which the volume was overestimated from the shadow area, the weight was overestimated in 16 and under- estimated in 3 indicating that these hearts were more dilated than is normal for diastole at rest. This same condition is, however, also true of the hearts in which the observed volume fairly closely corresponded with the estimated volume. Of the fourteen hearts in this group in 10 the weight was overestimated, in 2 underestimated. Of the total of 53 hearts studied in 15 the weight was under- estimated from the silhouette area, in 30 overestimated. We may therefore assume that the method used in preparing the bodies tended in the main to cause a somewhat greater disten- tion than is normal in diastole in the living under the conditions described above. We may likewise estimate heart volume from heart-weight, which we have assumed to be 0.55 per cent of the body weight. To determine a formula to express the relation of heart weight to diastolic heart volume we need to know the relation of heart weight to heart tissue volume and the relation of the volume of heart tissue to the volume of the heart and its contents in diastole. In order to estimate tissue volume from heart weight we have to determine the specific gravity of the heart. Vierordt, quot- ing Davy, gives 1049 as the specific gravity of the left ventricle. I have estimated the specific gravity of a considerable number of fresh dog hearts, of one unembalmed human heart and of numerous embalmed human hearts. The method used was to measure the displacement of the heart in oil and to estimate the specific gravity from this. The heart was in each case freed from extraneous substances but the subepicardial fat was left in place. The chief difficulty met with was to get rid of air bubbles. To aid in this the heart was cut into sections. For exact work the displacement should be measured in a vacuum but this was deemed unnecessary for the purpose in view. While there were individual variations, due chiefly to differences in the amount of subepicardial fact, the figure 1050 was selected as a 472 Cc. R. BARDEEN round number which expressed with fair accuracy the specific gravity of the heart as a whole. The volume of the empty heart in centimeters may therefore be taken as equal to the weight of the heart in grams divided by 1050. The ratio between the volume of the empty heart and that of the heart in diastole can be estimated from cadavers and from experimental work on animals. The chief difficulty lies in the determination of the volume of the heart in diastole. In order to determine the ratio between the volume of the empty heart in dogs and the volume of the heart in diastole, I have made a number of experiments in coéperation with Dr. J. A. E. Eyster and other members of the department of physiology at the University of Wisconsin. The dog was weighed and its pulse at rest under morphine was counted before beginning the experiment. The animal was then anaesthetized, the thorax opened and ligatures were placed about each of the vessels en- tering the heart. With the help of several assistants these liga- tures were tightened simultaneously at a given signal so as to close off the vessels during diastole. The heart was now re- moved from the body and its volume estimated. It was emp- tied and the volume of the cardiac tissue was measured and its weight determined. The ratio of the volume of the empty heart to that of the heart in diastole could then be ascertained. In order to make the pulse correspond approximately with the normal pulse as determined before the experiment, or some- what slower, the vagus nerve was stimulated during the experi- ment to the requisite amount. The chief difficulty in the ex- periment is that of tying off all the vessels simultaneously at the height of diastole. 7 Table 18 shows the result of six experiments. The percentage of the diastolic heart volume occupied by the blood in the heart chambers varied from 26 to 46 with an average of 40.6. It is probable that the smaller percentage represents a heart in which we did not succeed in tying off all the vessels in diastole. If we omit this heart the average becomes 43.5. The average empty heart volume in these dogs was therefore 59.4 per cent if ex- ‘periment 5 is included, 56.5 per cent if this experiment is not DETERMINATION OF SIZE OF HEART BY X-RAYS 473 included. It is of interest to note that the heart of the dog weighs more in relation to body weight than the human heart does and is subject to wider variations. ‘This is in accord with the observations of Joseph (08). In the human heart the percentage of the diastolic heart vol- ume occupied by the blood in the cavities appears to be greater than in the dog, the percentage occupied by the heart muscle less. In the study of embalmed cadavers the empty heart vol- ume was found to vary from 33.8 per cent to 80 per cent of the volume of the heart as a whole. The hearts, the outline of which seemed most closely to correspond with radiographic outlines of TABLE 18 Relation of diastolic volume to the volume of the empty heart in the dog WEIGH | porgx | WEIGHT |2ERCENT|pr.rorzc|| voruun | or | “UME | on Dog RATE HEART WEIGHT VOLUME EMPTY pepe: BLOOD Beare kilos grams 1 | 10.4 SOR Oeil 10 7G on) 102.64)" so8ek 73.9 41.9 Zr We 12).0 96 84.0 | 0.7 135.0 80.0 | 59.2 55.0 40.8 3 1) 10.2) 110 57.1] 0.56 106.0 60.0 | 56.6 46.0 43.4 4 | 13.0 for W250 0286 195.0 | 106.7 | 54.7 88.3 45.3 5 8.36} 120 70.0 | 0.84 90.0 66.7 | 74.0 26.0 26.0 6 | 16:0.) 120) . 135.5), 0.847 | 238.9) 129.0 | 54.0 | 10929 46.0 PANY GIG O Clstcess, o-0b8, od eee 0.801 59.4 40.6 the living diastolic heart, showed an average percentage of about 49.4 per cent heart tissue, 50.6 per cent heart chamber space. If the specific gravity of the heart be taken as 1050 and the per- centage of diastolic heart volume occupied by heart tissue be taken as 49.4 per cent we may estimate diastolic heart volume from heart weight by dividing the latter by 1.050 x 49.4 or 0.5187. The results thus obtained may be compared with the estimates given in tables A and B, in which the heart weight is estimated from the body weight and this in turn from the sil- houette area while the volume is estimated directly from the silhouette area. The use of round numbers in the tables gives rise to slight divergencies but otherwise the estimates of heart volume based on silhouette area and those based on heart weight correspond. ATA Cc. R. BARDEEN The ratio between heart volume calculated from heart weight in bodies studied in the anatomical laboratory and the meas- ured heart volume is shown in table 19. The hearts are grouped according to the extent of divergence of the observed from the calculated volume. Those showing less than 23 per cent of divergence are grouped together. The rest are grouped accord- ing to the nearest 5, 10, 15, 20, 25, 30, 35 and 45 per cent of TABLE 19 Hearts from cadavers grouped according to percentage of divergence from the assumed ratio between empty heart volume and diastolic volume AVERAGE ¥ EXTREMES OF PER CENT OF SEX HEART VOLUME DIVERGENCE PERCENTAGE OF | cupen OF cases ee Num- | HEART WEIGHT Male |Female ber BODY WEIGHT cases RATIO ‘ cc. +45 1 1 562 1 — 5.2 +35 1 1 470 il =13).2 +30 2 2 950-990 1 S11! 25 1 1 365 1 =i) 0 +20 7 (1 child) 6 i 75-687 6 ae (et!) +15 4 (1 child) 3 1 105-1000 4 + 3.2 +10 6 (1 child) 4 2 70-790 6 = 1 ap ty) 5 (1 foetus) 2 3 290-453 4 = 0.5 + 23 to —21 | 10 (1 child) 8 201" 167-810 8 es — 5 5) 5 0 210-700 7 — 026 —10 3 3 0 360-1155 2 + 4!5 —il5 D, 2 0 350-420 2 — 3.9 —20 4 (1 infant) 3 1 15-520 3 — 9.4 = 75) 1 , 1 0 320 otal. c. 2264| 52) 41 11 46 positive or negative divergence. Separate columns show the number of males and females in each group, the extremes of heart volume (including contents of chambers) and the average per cent of divergence from the ‘normal’ heart weight-body weight ratio of those of each group for which records were preserved. From this table it may be seen that while the greatest number (10) of hearts fall within the group assumed to show normal DETERMINATION OF SIZE OF HEART BY X-RAYS A475 diastolic volumes (+ 24 to — 24 per cent divergence), the number (27) of those which show a volume above what is assumed to be the normal diastolic volume is greater than the number (15) which show a volume smaller than the normal diastolic volume. This is what we should expect from the conditions of the hearts studied. The post-mortem condition of the heart has been studied by several investigators including MacWilliam (01) and Roth- berger (’04). At the time of death the heart is in diastole. The amount of blood in the heart depends on the general circulatory conditions at this time. After death there is a tonic contraction of the heart followed by a rigor mortis contraction. The post- mortem contraction of the heart is usually much greater in in- dividuals in whom the respiration stops before the circulation than in those in whom heart failure is a primary cause of death. The postmortem contraction is followed by a subsequent dila- tation but the extent of this depends to a large extent on the amount of fluid blood under pressure when the dilatation occurs. The bodies received at the Anatomical Laboratory at the University of Wisconsin have usually been dead at least a week. As a rule they are embalmed by injecting equal parts of alcohol, glycerine and carbolic acid into the femoral arteries and the thorax is not opened until the body is dissected. In some in- stances we have opened the thorax in order to study the condi- tion of the heart before embalming. As a rule the right atrium is fairly well distended with blood and frequently there is con- siderable blood in the right ventricle. While there is usually some blood in the left atrium this is less apt to be distended than the right atrium. The left ventricle is usually practically empty. When the embalming fluid is injected under a pressure of five or six pounds into the femoral arteries it usually enters the chambers on the left side of the heart and distends them to a moderate degree. The right side of the heart is less affected by the injection than the left side. The embalming fluid is usually followed by a shellac and Prussian blue arterial injection mass which also usually partially fills the chambers in the left side of the heart but not those on the right side. We have not meas- 476 Cc. R. BARDEEN ured the pressure of the fluid in the heart at the time of em- balming but it is probably considerably higher than the pressure in the heart during life at the beginning of systole. When the injection is completed both the right and left sides of the heart are probably as a rule more distended than is normal during life; the right as a result of natural factors active just before and follow- ing death, the left as a result of the pressure of the embalming fluid. The embalming fluid causes some shrinkage. The end result appears to be in many cases a heart having approximately the size of the living heart in diastole during bodily rest. The dilatation of the various chambers is probably seldom quite the same in the cadaver heart as in the living but the heart as a whole frequently appears not dissimilar in outline. If there has been an antemortem acute dilatation of the heart or if the em- balming fluid causes unusual distention we may have a heart large in proportion to the weight of its component tissue. If less blood than usual is sent into the right side of the heart before death or if the distention of the heart by the embalming fluid is less than usual or the shrinkage greater the size of the heart in relation to the weight of its component tissue is relatively small. The table shows that no clear relation exists between the weight of the heart compared to the weight of the body and the cadaver size of the heart compared with the weight of the empty heart. The best estimate which we can make of the ratio of heart substance to heart: content is on the one hand from the heart- weight-body weight ratio based on post mortem studies, on the other hand from the heart-silhouette area-body-weight ratio based on x-ray studies of the living. But it is of interest to see how closely the estimates thus made are approached by direct studies on the hearts of embalmed cadavers as shown in table 19. e. Ventricular output The chief interest in arriving at an approximate knowledge of heart content in diastole is in relation to the systolic output of the heart. Various methods have been used to determine the DETERMINATION OF SIZE OF HEART BY X-RAYS AT7Z amount of blood discharged from the heart at each systole. While the results have been far from uniform the results of the more recent work including that of Krogh and Lindhard (12) and Lindhard (’15) appear to indicate that the output of the human adult heart at rest is not far from 1 ee. per kilo of body weight per beat. Since the weight of the heart substance may be esti- mated at 5.5 gr. per kilo, its specific gravity as 1050 and its vol- ume at about 49.4 per cent of the volume of the heart in diastole the volume of heart content in diastole may be estimated as 5.365 ce. per kilo. About 20 per cent of the blood in the heart in diastole is thus sent into the aorta at each systole during rest. If we estimate one-third of the blood in the heart during diastole to be contained in each ventricle and one-third in the two atria we have 60 per cent of the contents of the left ventri- cle sent into the aorta at each systole during bodily rest. In the upright position the diastolic heart is smaller than in the sitting position and in the sitting position than in the prone position. It appears that to the lessened hydrostatic pressure in the inferior vena cava and to the moderate exertion accom- panying sitting and standing the heart accommodates itself by beating faster, contracting more completely during systole, and expanding less during diastole. Nicolai and Zuntz have shown, however, (14) that during severe exercise the heart expands more during diastole than when at rest. Muscular action acts as a pump to force blood toward the heart. In all probability the heart also contracts more completely so that the output of the heart is increased by pulse volume as well as by pulse rate. The experimental work of Henderson and Barringer on the dog which has led these investigators to opposite deductions does not seem to me at all conclusive. In order to test the estimate of heart content in diastole given above and to estimate the reduction in size of the heart during systole we have devised with the collaboration of Dr. J. A. E. Eyster, an apparatus for taking ‘instantaneous’ radiographs of the heart at any desired period of the cardiac cycle. The mechanism is adjusted to the carotid pulse. As a rule two successive radiographs are taken on the same plate, one at the THE AMERICAN JOURNAL OF ANATOMY, VOL. 23, NO 2 478 Cc. R. BARDEEN height of systole, one in diastole and the outlines of the two superimposed shadows are compared. The pictures are taken at the usual distance of two meters. Two intensifying screens are used, one on each side of a photographic film. Drum tracings of the respiration, carotid pulse and of the period of exposure are made while the pictures are taken. The estimates of change of heart volume from diastole to systole based on these plates correspond well with the data given above as the following table will show (table 20). In the sitting position observations were made on sixteen in- dividuals. For one individual two: sets of observations are recorded in the table. During the change in heart volume from diastole to systole blood from the ventricles is forced into the pulmonary artery and aorta. Since the systolic picture was taken as nearly as possible at the height of ventricular systole it is possible that in most cases diastole had already begun in the atria and some new blood had entered these chambers. The actual output of the heart may therefore have been some- what greater than that estimated from the change in the size of the silhouette area fron diastole to systole. We have however shown above from studies on cadavers that there is a tendency to underestimate volume from silhouette area when the heart is contracted so that to some extent the error due to diastole filling of the atria is offset by the error due to underestimation of volume from silhouette area. The average output per beat in the sitting position was esti- mated as 37.8 per cent of the cardiac contents or 18.9 per cent from each ventricle. This corresponds closely with the 20 per cent estimate based on the work of Lindhard, as outlined above. The lowest output was 27.4 per cent of the cardiac content or 13.7 per cent from each ventricle. The largest was 58.2 per cent or 29.1 per cent from each ventricle. If we estimate the ventric- ular content as 334 per cent of the blood in the heart in the lat- ter case the ventricle was nearly completely emptied at each contraction while in the former case it was less than half emp- tied. In eight out of the sixteen cases the per cent of cardiac blood expelled varied from 39.2 per cent to 41.8 per cent or close DETERMINATION OF SIZE OF HEART BY TABLE 20 X-RAYS 479 Volume of heart estimated from diastolic and systolic silhouette areas, difference im volume, percentage of reduction in heart volume and percentage of heart blood expelled during systole a 3 } = S S a as Be SUBJECT S 5 4 Semoats REMARKS 4 = a a5 % 5 8 S oy 58 | 2 D E eo | aS 5 a a Caan ee GCs cc. Gee A. Sitting position J. F.S., 5’ 10”, 135 Ibs.......|691..2/595.8) 95.4) 13.8 | 27.4 E. J. V., 5’ 63’, 148 Ibs..... .{861.8/741 .0|120.8|140.3 | 7.8) Enlarged heart E. F. S., 5’ 9’’, 155 lbs....... ./723.9/619.2)104.7) 14.46] 28.7 rare f{|675 .0|580.0| 95.0) 14.1 | 27.9) LE AN a | 699 .0|590.0}109.0| 15.6 | 31.0 JOG, 5 3% 115) bss. + 2.-|620701522/0) 98.0) 15.8 | 31.3 R. W. T., 5’ 81’, 143 lbs..... .1667. 4/555 .6/111 .8) 16.75) 33.3) pes DAG 4 GO bse 3th) ats: 862 .0/692.0)170.0) 19.72) 39.2 (CC OVE OVO, UGS Lbsiea 5. 732 . 91587 .8|145.1| 19.8 | 39.3 Crores Oe lO ola bse asce 2 612.0/490.0|122.0} 19.93) 39.5 C. E. G., 5’ 114”, 164 lbs... . ./775.0,619.0)156.0) 20.13} 40.0 Av Weeote Ae 229) Noses. 3d cacti 657 .8]522.0)135.8) 20.64} 41.0 S. A. M., 5’ 8’’, 171.5 lbs... .../658.41522.0/186.4| 20.72) 41.2 P. M. D., 5’ 113’’, 146.3 lbs... |676.0/535 0/141 .0| 20.85} 41.3 F. C. K., 5’ 8’, 154 lbs......../750.0/586 .0/164.0] 21.87) 41.8| Rather large heart Ee Wes: We 142Ibs ee 699 .6)/514.0/185.6| 26.25} 56.1 Crys a? dO"; 145 lbsxseske 715 .8|506 .0/209 .8} 29.3 | 58.2 PAR CT EVE C ner serie. cia weve Micra Sua ORT oye | eres een 19.04| 37.8 B. Prone position E. J. V., 5’ 64’, 148 lbs..... . .|887.0/792.3] 94.7) 10.68) 19.2 R. W. T., 5’ 8}’’, 143 lbs.... . .|658.9|579.6| 79.3] 12.04) 23.9) W. E. G., 5’ 43’’, 130 Ibs... . .|603.0|522.0] 81.0] 13.43] 25.4! J. F.S., 5’ 10’’, 135 lbs....... . 741.9635 .2/106.7| 14.38) 28.5 E. F.S., 5’ 9’’, 155 Ibs...... . .|723.9)619.2|104.7) 14.46) 28.7 H. A., 5’ 92’’, 152 lbs........./699.0}590.0)109.0). 15.60) 31.0 M. D. W., 5’ 9’’, 1387 lbs...... .|851.8/715.8/136.0} 15.96) 31.7 C. E. G., 5’ 114’, 164 lbs..... .|835.6/698.7|136.9) 16.39) 32.5 NSERC NORE Bie Ova, 5 dry Gi vcore paces | Okcee Oke | RR Nee renee 14.1 | 27.6) 480 Cc. R. BARDEEN to the estimate given above of 20 per cent from each ventricle, 60 per cent of the ventricular content. In the prone position we have observations on eight individ- uals. The average output was 27.6 per cent of the cardiac con- tent or 13.8 per cent for each ventricle; 41.4 per cent of the ventricular content. The extremes are 19.2 per cent of the car- diac content, 9.6 per cent for each ventricle, 29 per cent of the ventricular content; and 32.5 per cent of the cardiac output, 16.8 per cent for each ventricle, or 50.4 per cent of the ventricu- lar content. The estimates of percentage output of ventricular content are based upon the assumption that one-third of the blood in the heart in diastole is to be found in each ventricle, one-third in the two atria. It is probable however that in the prone position a greater proportion of the blood in the heart in diastole is to be found in the atria and that the percentage output from each ventricle is greater. On the assumption that in the prone position there is an equal amount of blood in each chamber of the heart in diastole the percentage output from each ventricle would average 55.2 per cent, with variations from 38.4 per cent to 62 per cent. The ‘relation of cardiac output as determined by the method given above, to various factors has been studied in our labora- tories by Mr. E. J. Van Liere. He found no correlation be- tween body weight, height, or build and the proportional amount of blood expelled at each contraction of the heart. Hearts whose diastolic volume was 5 per cent or more above the normal as compared with body weight showed less proportional cardiac output than normal and small hearts. High pulse pressure was accompanied by large relative output in a given position, al- though in the prone position the pulse pressure was higher than in the sitting position while the relative output was smaller. No definite correlation between systolic pressure or pulse rate and output was found under the conditions of the experiment. The average ieft ventricular output sitting was 80.8 cc. per kilo per minute, the average pulse rate 82 making the output approximately 1 cc. per kilo per beat. The average output DETERMINATION OF SIZE OF HEART BY X-RAYS 481 lying was 56.9 ec. per kilo per’ minute with a pulse rate of 67 or 0.85 ee. per kilo per beat. f. Relation of size of heart to heiqht, age and sex In the preceding sections we have considered heart size chiefly from the standpoint of body weight with which it 1s most closely correlated. In case of a given individual, however, other fac- tors than merely body weight must be taken into consideration before we can form an accurate judgment as to whether or not the size of the heart is normal for that individual. Of these other factors the chief are height, age and sex. The size of the heart for a given body weight is estimated in the tables on the assumption of normal height for that weight for a given sex and age. The chief studies on the relations of weight, height, sex and age in the adult have been made by the insurance actuaries. The most important of these studies is the Medico-Actuarial Mortality Investigation vol. 1 published by the Association of Life Insurance Medical Directors and the Actuarial Society of America. For the period of childhood and youth we have a large number of studies made on school children of which special mention may be made of those of Roberts C7883). He. Pe Bowditeh! (755479, 9), > Burk. (98) a Key. (89), F. Boas (96-97), Hastings, W. W. (’02), Baldwin (14), W. T. Porter (94) and Ethel M. Elderton (14-15). The pio- neer work in this general field is that of Quetelet (32, ’48). These studies have shown that a closer correlation between height and weight is found if age and sex be taken into considera- tion than if these are ignored. The figures given in tables A and B are based upon an analysis of the data available in the literature together with studies made in the Clinical Department at the University of Wisconsin. A full account of these studies is reserved for publication in a subsequent paper. The figures for height are those which these studies have led us to believe represent a fair normal average for a given weight, for the age and sex indicated in healthy Americans. Weight means weight without clothes; height, height without shoes; age, age at nearest birthday. 482 Cc. R. BARDEEN Table A gives figures for childhood and youth. Table B gives figures for adults at three ages, 20, 30, and 50. In making use of these tables one compares the parellel ray silhouette area of the heart of the individual under consideration (a) with the silhouette area given by the table as normal for a person of the individual’s weight and (b) with the silhouette area normal for a person of the individual’s height, sex and age being taken into consideration. If the silhouette area is normal for weight or for height or is intermediate between the two we consider that the heart is one of normal size. If the heart volume correspond- ing to the silhouette area is more than 10 per cent too large both from the standpoint of height and of weight we consider that it is disproportionately large. If it is correspondingly small both from the standpoint of height and of weight we con- sider it disproportionately small. Our own practice is thus to estimate cardiac size in percentage of variation of volume from that assumed as normal for height and from that assumed as normal for weight. For instance we will suppose that a man 30 years of age 5’ 10” tall and weighing 150 pounds shows a heart silhouette area (reduced about 6 per cent to allow for divergence of rays if a radiograph is used) of 120 sq. em. From table B we find that an area of 120 sq. em. corresponds to a volume of 696 cu.em. Fora weight of 150 Ibs. we should expect a volume of 723 cu.em. Inaman 5’ 10” tall at 30 years of age we should expect a volume of 768 cu. em. The heart of the individual under consideration is therefore 27 cu. em. or 3.7 per cent below the standard from the standpoint of weight, 72 cu. cm. or 9.1 per cent below the standard for height. A slight variation of this kind is within the limits of error of the method used and the heart would be considered of normal size. In conclusion I desire to thank the members of the staffs of the departments of anatomy, physiology and clinical medicine and Prof. Max. Mason of the department of physics for valuable aid in carrying out the investigations described in this paper. DETERMINATION OF SIZE OF HEART BY X-RAYS 483 LITERATURE CITED ALBERS-SCHONBERG 1908 Die Bestimmung der Herzgrésse mit besonderer Beriicksichtigung der Orthophotographie. Fortschritte aus der Gebiete der Roentgenstrahlen, Bd. 12, p. 38. Batpwin, B. T. 1914 Physical growth and school progress. United States Bureau of Education Bulletin no. 10. BarpDEEN, C. R. 1916 A standard of measurement in determining the relative size of the heart. Anat. Rec., vol. 10, p. 176. BENEKE, F. W. 1878 Die anatomischen Grundlagen der Constitutions-Anoma- lieen des Menschen. Boas, F. 1896-1897 Growth of children, U. S. Bureau of Education, Report, vol. 2, p. 1541-1599. Bowpitca, H. P. 1875, 1879, 1891 The growth of children. Mass. Board of Health Reports. Boyp 1861 Phil. Trans. Royal Soec., London, vol. 151, Pt. 1. Burk, F. 1898 The growth of children in weight and height. American Journal of Psychology, vol. 9, p. 253-326. Cuaytor, T. A. anp Merriti, W. H. 1909 Orthodiagraphy in the study of the heart and great vessels. Amer. Jr. of the Med. Sc., vol. 138, p. 549. DererRMANN, W. 1900 Die Beweglichkeit des Herzens bei Lageveranderungen des Kérpes. Zeitsch. f. klin. Med., Bd. 40, p. 24. Dretien, H. 1906-1907 Uber Grosse und Lage des Herzens und ihre Abhingig- keit von physiologischen Bedingungen. Deut. Archiv f. klin. Med., Bd. 88, p. 55. DintiteNn, H. 1909 Klinische Bedeutung der Veriinderungen am Zirculations- apparet bei wechselnder Kdérperstellungen (Liegen and Stehen). Deut. Arch. f. klin. Med., Bd. 97, p. 132. Experton, Erser M. 1914-1915 Height and weight of school children in Glasgow. Biometrika, vol. 10, p. 288. GinceL, R. 1914 Die Klinische Verwertung der Herzsilhouette. Miinch. Med. Wochenschrift Bd. 61, p. 220. GroepEL, F. M. 1910 Beobachtungen iiber den Einfluss der Respiration auf Blutdruch auf Herzgroésse. Zeitschr. f. klin. Med., Bd. 70, p. 47. GREENWOOD AND Brown 1913 , cee 175 DvuesserG, J. Chondriosomes in the testi- ele-cellsyon vem Uls es afeicisccieteie icles eteress/elere 133 | ere of turtles. The formation and struc- ture of the zona pellucida in the ovarian. 237 Embryos. On the age of human.......... Bo Gill Embryos with a note on similar structures in reptiles. Vestigial gill filaments in chick. 205 ILAMENTS in chick embryos with a note on similar structures in reptiles. Ves- (ateaeail, fori lS ae aie Sad Ota leceairs 205 Fontanella metopica and its remnants in an Gye hvilbie irl LAS hoy eenee heads canwaoohoe 259 Formation and structure of the zona pellucida in the ovarian eggs of turtles. The...... 237 Frog larva—observation and experiment on the living animal. Studies on the growth of blood-vessels in the tail of the.......... 37 Fundulus. Chondriosomes in the testicle- Cells) Of his rare reclaniaten croaiiennsteeces 133 ILL filaments in chick embryos with a note on similar structures in reptiles. WWiEStiei al map eertmeney ely ateeee ai cstetars ucuctoielere! Ve 205 Hee by means of the x-rays. Deter- mination of the size of the.. .......... 423 Heart-beat upon the development of the vascular system in the chick. The effect Of thet s ere te eroe bone etag doen 175 Human embryos. On the age of............ 397 Humerus of man. The position of the inser- tion of the pectoralis major and deltoid muscles! OM theseaeseeerenitcsrasnecsee cee 155 OHNSON, FRANKLIN PARADISE. The isolation, shape, size, and number of the lobules of the pig’s liver................ 273 | eee Asram T. The branchial plexus of nerves in man, the variations in its formation and branches 316.605 Son 285 ARVA—by observation and experiment on the living animal. Studies on the growth of blood-vessels in the tail of the 1080) SR Ren DESO nonce dociyc)s.5 ool eee 37 Liver. The isolation, shape, size, and num- ber of the lobules of the pig’s............ 273 Lobules of the pig’s liver. The isolation, shape, size, and number of the........... 273 Luteum in the ovary of the chicken. Sex Studies oX. Lhe(corpussepeeeeee ees cc 1 ALL, FRANKLIN P. On the age of human EMbDEVOSSs sic eee O eee 397 Man, the variations in its formation and branches. The brachial plexus of nerves TD 0s (9s web aichay aks: caw noc ata e e is 285 Metopica and its remnants in an adult skull. whe) fontanella..o ae ane. reOo Muscles on the humerus of man. The posi- tion of the insertion of the pectoralis major and! deltoid: «..<\<:..0 gee oe eee es tes 155 ERVES in man, the variations in its for- mation and branches. The brachial plexus) Of... sos siacsotenciooemeiehioe seis'elc 285 @* ARIAN eggs of turtles. The formation gad structure of the zona pellucida in Ona ae the chicken. , Sex studies. X. The Corpus) luteum) inythereeeeeeereaeee ccc EARL, RAYMOND AND Borine, Auice M. Sex studies. X. The corpus luteum in the ovary of the chicken... ............. Pectoralis major and deltoid muscles on the humerus of man. The position of the in- sertion/of thes preemie ce esc ccceeee « 155 Pellucida in the ovarian eggs of turtles. The formation and structure of the zona...... 237 Pig (Sus serofa). The fate of the ultimobran- chial bodies in the.....-. 89 Pig’s liver. The isolation, shape, size, “and number of the lobules of the... 273 Plexus of nerves in man, the variations in ‘its formation and branches. The branchial.. 285 EPTILES. Vestigial gill filaments in chick embryos with a note on similar AULICHITES PLL el tdlepal-lese sis'e.eloie elelstets;= alain ioe 205 489 490 ° CHULTZ, Avotr H. The fontanella me- S topica and its remnants in an adult skull. Scuutrz, Apotr H. The position of the in- sertion of the pectoralis major and deltoid muscles on the humerus of man.......... Sex studies. X. The corpus luteum in the Ovary OL thevehicken ees. - ose eee ie Size of the heart by means of the x-rays. termination voteube: 6. 6.3.0 seceiaaeeloeens Skull. The fontanella metopica and its rem- MANS ID ANUAAUIG | ok oe eee eee eee Structures of the zona pellucida in the ovarian eggs of turtles. The formation and...... Te of the frog larva—by observation and Stud- INDEX 259 Turina, Aticr. The formation and structure of the zona pellucida in the ovarian eggs Of turtles? ves-ctcn wns eu eee eee ore ; Turtles. The formation and structure of the 237 zona pellucida in the ovarian eggs of...... 237 Le bodies in the pig (Sus scrofa). The fate of the.......... YASCULAR system in the chick. The effect of the heart-beat upon the de- velopment) Of the poe. --o-h eee ey. Vestigial gill filaments in chick embryos with 175 a note on similar structures in reptiles.... 205 -RAYS. Determination of the size of the heart by means of the...........-++-+.<- 4 Y Aarts pellucida in the ovarian eggs of tur- tles. The formation and structure of es om | | | ui | 1] TCO Cave ecru ey Et ay SITET het an PEC CED LODO Tar CoO Cnet ISHS HEV ECU CHOOT Oto in Waiter? 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