SPECIFIC GRAVITY OF THE LUNGS. 329 those of others that have lived and breathed for some time after birth, no perceptible difference was found in the quantity of blood existing in the vessels in the two cases. The fact is, the excess of blood after the establishment of respiration is distributed throughout the minute capillary system of the lungs : it does not remain in the large trunks. The state of the pulmonary vessels, therefore, furnishes no evidence either of respiration or the contrary. The same observation will apply to the presence of blood in the substance of the lungs. It is said that on cutting through lungs that have breathed the incisions are followed by a copious flow of blood; this, it is alleged, does not happen with lungs that have not breathed. In performing this experiment on the lungs of new-born children, the author was not able to perceive any well-marked difference in quantity, but the blood which escapes on pressure from lungs that have breathed is frothy. The blood may be found coagulated or not, and there is no difference in this condition, whether the child is born living or dead. 8. Relative proportion of fat in the lungs.-In 1847, Guillot proposed to determine the question of respiration by the relative proportion of fat contained in the lungs before and after birth. According to him, the quantity of fat contained in the pulmonary tissue is always greater before than after respiration, and it begins to diminish from the moment that the act of breathing commences. Before respiration, the dried lungs yield from 10 to 18 per cent. of fat; after respiration, not more than 6 per cent. The process followed by Guillot is to dry the organs at a high temperature, so as to expel all the water, reduce them to powder, and digest this powder in ether. (Comp. Rend.' 1847, p. 777.) It need hardly be observed that this process could not be made available in practice. Admitting the facts as stated, the assigned difference between 6 and 10 per cent. may disappear by further observations. The process, however, is open to this objection: -If respiration has been fully performed, this will be sufficiently evident from the state of the lungs; and if imperfectly performed, as the change is alleged to depend on the respiratory act, the result of an analysis would not remove the difficulty. 9. The specific gravity of the lungs.-The specific gravity of the lungs is greater before than after respiration; for although the organs become absolutely heavier by the establishment of the process, this is owing not to the air, but to the additional quantity of blood received into them. The air thus received so increases the volume of the lungs as to more than counteract the additional weight derived from the blood, and thus apparently to diminish their specific gravity. Under these circumstances they readily float on water. The author found that the specific gravity of the lungs before respiration, i.e. in the foetal condition, varied from 1.04 to 1:05. They are about one-twentieth part heavier than their bulk of water. After respiration, the specific gravity of the lungs with the air contained in them was found in one experiment to be 0.94, i.e. the organs were about oneseventeenth part lighter than their bulk of water. The introduction of a small quantity of air will render these organs buoyant in water, and an alteration in the volume of the lungs sufficient for this purpose would not be perceptible to the eye. It will be understood that the specific gravity of the substance of the lungs is unchanged; the organs are rendered only apparently lighter by the air contained in their cells, on the same principle as a distended bladder. Hence it follows that the apparent diminution of specific gravity will take place whether the air be derived from respiration, artificial inflation, or putrefaction. It is on this property of the lungs that the application of what is termed the hydrostatic test, or the docimasia pulmonaris, is founded-a subject which may be appropriately considered in another chapter. Conclusions.-The general conclusions which may be drawn from the contents of this chapter are :— 1. That a child may be born alive and be criminally destroyed before it has breathed. 2. That the presence of any marks of putrefaction in utero proves that the child must have come into the world dead. 3. That the characters accompanying certain marks of violence may occasionally show that the child was living when the violence was applied to it. 4. That there are no certain medical signs by which a child which has not breathed can be proved to have been living when it was maltreated. 5. That a new-born child may be destroyed by the prevention of respiration during delivery. 6. That the proof of respiration shows that the child has breathed, not that it has been born alive. 7. That by taking together the colour, volume, consistency, appearance of developed air-cells, absolute weight, and buoyancy of the lungs, we may be able to draw an inference whether the child has or has not breathed. 8. That the lungs increase in weight according to the degree to which respiration is established, and not necessarily according to the period which the child has survived birth. 9. That no reliance can be placed upon the test of Ploucquet, or the proportionate weight of the lungs to the body. 10. That no reliance can be placed either upon the relative quantity of blood in the pulmonary vessels, or upon the relative proportion of fat contained in the pulmonary tissue, as evidence of respiration having been performed. CHAPTER 76. MODE OF EMPLOYING THE HYDROSTATIC TEST-INCORRECT INFERENCES-SINKING OF THE LUNGS FROM DISEASE OR ATELECTASIS-LIFE WITH PARTIAL DISTENSION OF THE LUNGS-LIFE WITH PERFECT ATELECTASIS OR ENTIRE ABSENCE OF AIR FROM THE LUNGS-ERRONEOUS MEDICAL INFERENCE FROM SINKING OF THE LUNGS-FLOATING OF THE LUNGS FROM EMPHYSEMA AND PUTREFACTION— EFFECTS OF PUTREFACTION IN AIR-GENERAL CONCLUSIONS. Mode of employing the hydrostatic test.-The hydrostatic test has been long known, and various opinions have been entertained relative to its efficiency and value. Many of the objections that have been urged to its use appear to have arisen from a mistaken view of the evidence which it is capable of furnishing. When the hydrostatic test is properly applied, and with a full knowledge of the exceptions to which it is exposed, it will afford in many cases good evidence whether a child has or has not respired. The mode of performing the experiment is extremely simple. Having removed the lungs from the chest, they should be placed, still connected with the trachea and bronchi, upon the surface of distilled or river water. If they sink it should be noted whether the sinking takes place rapidly or slowly. If they both sink, the two lungs should be tried separately; for it is sometimes found that one, commonly the right, will float, while the other will sink. Supposing that both lungs sink, it will then be proper to divide each into twelve or fifteen pieces, and place these pieces separately on water. If, after this, they all sink, the inference is, that although the child may have lived and survived its birth, there is no evidence of its having breathed. On SINKING OF THE LUNGS FROM DISEASE. 331 the other hand, the organs when placed on water may float: it should then be noticed whether they float high above the surface, or at or below the level of the water. Sometimes they indifferently float or sink. These differences will lead to a conclusion respecting the degree to which respiration has taken place. It will now be proper to separate the lungs, and determine whether the buoyancy is due to one or both. Each lung should be divided, as before, and each piece separately tried. If all the pieces float, even after firm compression, we have good evidence, cæteris paribus, that respiration has been very perfectly performed. Should any of the divided portions sink in water, either before or after compression, our opinion should be modified accordingly. Some have recommended that the lungs should be placed on water with the heart and thymus gland attached; but there appears to be no good reason for this, since it is as easy to form an opinion of the degree of buoyancy possessed by the lungs, from the readiness with which they float, as by observing whether or not they have the power of supporting these two organs. Such, then, is the method of employing the hydrostatic test in cases of infanticide. With regard to its use in medical jurisprudence, it should be observed that the floating of the lungs in water is not, as it is often incorrectly represented to be, a proof that a child has been born alive: nor is the fact of their sinking in water any proof that a child was born dead. The floating, under the limitations to be now described, proves only that a child has breathed; the sinking, either that it has not breathed, or breathed but imperfectly. The fact of a child having been born living or dead, has, strictly speaking, no relation to the employment of the hydrostatic test. There are, indeed, cases of infanticide which may be readily established without resorting to this test: all that the law requires is proof of a child having been born living-whether this proof be furnished by the state of the lungs through the hydrostatic test, or in any other manner, is of no moment. The signs of life are commonly sought for in the lungs, because it is in these organs that the changes produced by a new state of existence are first perceived: but this examination may be dispensed with, when others have seen it manifest life by motion or otherwise after its birth; or in cases where, without being seen, it has been heard to cry. The crying of a child has been admitted as evidence of live birth on several trials for infanticide; although, as it is elsewhere stated, a child may utter a cry and die before its body is entirely born. Among the objections which have been urged to the employment of the hydrostatic test, we have first to consider those which concern the sinking of the lungs in water. SINKING OF THE LUNGS FROM DISEASE OR ATELECTASIS. It is said that the hydrostatic test cannot show whether a child has or has not survived its birth, because the lungs of children that have lived for a considerable period have been observed to sink entirely in water. In some instances this may depend on disease, tending to consolidate the aircells, as hepatization, or scirrhus-in others, on ædema, or congestion; but these cases can create no difficulty, since the cause of the lungs sinking in water would be at once obvious on examination. The hepatized portion of lung may be known by the firmness with which it resists cutting with the knife, as also by the fact that it is impossible to distend it artificially with air. On the other hand, there are cases in which the lungs appear healthy and unaffected; and all that we can perceive is, that they retain their foetal condition. This is a very different state from that of hepatization, because the lungs may, in this foetal condition, be made to receive air by artificial inflation. It is remarkable that life should continue for many hours and sometimes even for days, under such a condition; but the occasional existence of this state of the organs in a living child is placed beyond all dispute; the explanation of the causes upon which it depends-how it is that a child may live and breathe for hours or days, and no signs of respiration are discovered in its body after death, is, however, involved in great difficulty. The researches of Jörg have thrown some light upon the subject: and these may probably lead the way to other discoveries in this obscure department of physiology. Some of Jörg's views are peculiar. He considers that the act of parturition, as well as the duration of the process, has a material influence upon the system of a child; and that these conditions serve to prepare it for the efforts which it has to make in performing respiration. (Die Fötuslunge,' Grimma, 1835.) Supposing the first inspiration made by a child to be, from any cause, feeble or imperfect, then the organs become only partially distended; and the remaining portions will preserve their foetal condition. Jörg considers this as a positively diseased state of the lungs in the new-born child, and he has given it the name of atelectasis Fig. 153. Atelectasis of the lungs in a new-born child, from Jörg. a b Larynx and windpipe. c The right lung, the upper and lighter portion containing air. d The darker and lower portion in a state of atelectasis (uninflated). e The left lung. f A portion of this lung in a state of atelectasis, with small patches of a lighter shade which have received air. 9 The heart. The thymus gland. i The aorta. k The pulmonary artery. will (ἀτελὴς, ‘incomplete; ἔκτασις, expansion'). It may proceed from various causes. He considers that children that are born after an easy and rapid delivery are subject to it; and thus it may be found in a mature, as well as in an immature child. Any cause which much weakens the vital powers of a child before its actual birth may give rise to the occurrence of this imperfect expansion of the lungs. In this way it may be due to longcontinued pressure on the head during delivery, or to bleeding from the cord. All the causes of asphyxia in a new-born child will, when operating only in a slight degree, also produce this atelectasic condition. A part of the lung is, in the first instance, distended with air, but the child may not have sufficient strength to fill the remaining portions; it may thus live on for some hours or days, respiring at intervals, and becoming occasionally convulsedin which state it will probably sink exhausted and die. Jörg has remarked, that those portions of the lung which are not speedily distended with air become afterwards consolidated or hepatized, so that all traces of their cellular structure are lost. The length of time which a child survives will depend upon the degree to which its lungs have become dilated. This condition of the lungs is sometimes to be clearly traced to the diversion of the blood from these organs, by reason of the ductus arteriosus or foramen ovale remaining open after birth. Life with partial distension of the lungs.-It is not necessary that the whole of the lungs should have received air in order that a child should continue to live even for several months after its birth. A child aged six months had been, it was supposed, destroyed by suffocation. Upon opening the chest, the viscera were found healthy; but the whole of the inferior lobe of the right lung was, so far as regarded colour, density, and structure, precisely like the lungs of a foetus, no air having ever penetrated into it. It had become developed in size, but its cellular structure was completely wanting. When the whole of the lung was placed in water, it floated; but THE LUNGS IN NEW-BORN CHILDREN. 333 when the inferior lobe was separated, it immediately sank to the bottom of the vessel. No doubt this was a case of partial atelectasis, such as it is described by Jörg. This portion of the lung had not received air in the first instance; and it had become afterwards consolidated or hepatized, so that it could not be inflated. The illustration, fig. 153, p. 332, represents the condition of the lungs described by Jörg under the name of atelectasis. A child aged five weeks died suddenly, and its death was attributed to an opiate, although the circumstances rendered it highly improbable that the child had died from poison. The body was good condition. The lungs were found lying at the back part of the chest, inelastic, and presenting no crepitation in any part. They had the usual appearance of the unexpanded lungs of the foetus. They weighed 1,080 grains. They sank in water, and when divided into many pieces no portion of them floated. It was difficult to inflate them, and the portions inflated readily lost the air by compression and sank. The microscope showed an absence of cellular structure. It is surprising how the child could have lived so many weeks with this state of the lungs; and it is obvious that under such circumstances a very slight obstruction to respiration would suffice to account for its sudden death. ('Lancet,' 1868, 1, p. 810.) Albert met with a case, in which a child died thirty-six hours after its birth, having been attacked with convulsions at intervals during that time. On inspection, the whole of the right and the lower portion of the left lung were found to be in their foetal condition, and they immediately sank when immersed in water. There was no diseased appearance in the organs, and the undistended portions were easily filled by blowing air into them. This, indeed, is the test of this condition. The lungs are not diseased, but simply unexpanded. (Henke's 'Zeitschr.' 1837, 2, p. 422.) Dépaul found that in many cases in which children had died suddenly after breathing for several hours or days, there was no other morbid appearance to be perceived than an unexpanded condition of a large portion of the lungs. ('Med. Gaz.' vol. 39, p. 283.) Life with perfect atelectasis, or entire absence of air from the lungs.—It is necessary for a medical jurist to be aware that this state of the lungs, which is here called atelectasis, is by no means infrequent among new-born children. When no portion of air is found in the lungs of a child, there is no test by which such a case can be distinguished from one in which the child has come into the world dead. These cases of atelectasis are ordinarily set down as exceptions to a general rule; but the numerous cases subjoined will show that they are more common than some medical jurists are inclined to admit. In examining the body of a child, the history of which is unknown, the possible occurrence of these cases should be well borne in mind. It is not improbable that many such come yearly before coroners, and that they are dismissed as cases of still-born children, notwithstanding that marks of murderous violence are often found upon the bodies. If, as it has been already observed, the lungs sink in water, this fact alone is commonly regarded by a medical man as sufficient evidence of still-birth. This is assuredly putting an incorrect interpretation on the facts, and it may throw obstacles in the way of a judicial inquiry, and lead to the concealment of crime. Bernt met with an instance in which a seven-months' child died two hours after birth; and when its lungs were divided and placed in water, every fragment sank. Remer reported a case, in which the lungs sank in water, both entire as well as when divided, although the child had survived its birth at least four days. (Henke, 'Lehrb. der Gerichtl. Med.' p. 374.) In this case the navel-string separated naturally before death. Orfila found, in a child which had lived eleven hours, every portion of the lungs when divided, to sink on immersion. In three other instances, in which the |