EXAMINATION" JOE .BONES 79 (7) Bones, particularly the ends of the long bones, should be examined very minutely and carefully to find out if they have been cut by sharp cutting instruments or sawn or gnawed through by animals and the medulla eaten away. Sometimes inexperienced police-officers mistake the gnawing of bones by animals for cuts by sharp instruments, and then try to suggest all kinds of absurd theories to maintain their point. Their nutrient canals should be examined for the presence of red arsenic or some other stain to ascertain if the bones came from a dissecting room as the pleader m a city where there is a medical school or college may raise the question as to whether they came from a dissecting room. To avoid such a possibility it is necessary for the authorities to see that all remaining parts are thoroughly incinerated after dissection is over. (8) It is almost impossible to infer the cause of death from a bone or bones unless there is evidence of fractures which would, under normal con- ditions, prove fatal, e.g. fractures of the skull bones or of the upper cervical vertebrae or a deep cut into any of these bones suggesting the use of a heavy- cutting instrument, such as a gandasa or fracture of several ribs. Disease of the bones, such as caries or necrosis, should also be noted, if present. Bones should not be returned to the police after medical examination, but should be retained and kept in one's own custody with a view to pro- ducing, them in court, if required. Burnt Bones.—In some instances burnt tones and ashes are forwarded to the medical officer for inspection, when the police come to suspect some foul play after a body is partially or completely burnt. If the. body is not completely consumed, fragments of bones left would afford sufficient evidence to say that they were human or not. The combustion of a body is rarely so complete as to reduce it to ashes. Hence, by shifting the ashes through sieves fragments of bones can be collected and identified by a careful study. Fig. 21.—Fragments of burnt bones identified as Jhuman bones. (From a photograph lent kindly by Dr. M. A. Khan.) A bone, when burnt in the open, is white in appearance, and black or ash grey, when burnt in a closed fire. A burnt bone preserves its shape, but falls to powder when pressed between the fingers. It is said that it will be reduced to charcoal if treated with hydrochloric acid, but this is not necessarily true. If it is so much burnt that organic matter is destroyed no charcoal will be left on adding acid.