Page:Medical jurisprudence (IA medicaljurisprud03pari).pdf/131

 sirous of procuring additional evidence, respecting the existence of respiration, from the condition of the pulmonary organs, proposed a test founded on the absolute weight of the lungs compared with that of the body. Respiration produces two important changes in them—by inflating their texture it diminishes their specific gravity; and by promoting a determination of blood to their vessels, it increases their absolute weight; upon the former of these changes, the hydrostatic test is founded, as we have already explained; on the latter, Professor Plouquet endeavoured to found his "Nova Docimasia Pulmonaris," which is now very generally known by the name of Plouquet's test, or assay. The blood-vessels, observes this distinguished physiologist, being collapsed and compressed in the lungs of the fœtus, admit only a small portion of blood; but after respiration, being dilated, and extended, and more free in the expanded lungs, they receive a greater quantity; in consequence of which they become still farther expanded, and of greater calibre. As this increased capacity of the vessels is necessarily permanent, a greater quantity of blood will remain after death in the arteries and veins, and more especially in the latter, than in the lungs of those infants who have never respired, and consequently the absolute weight of the lungs must be increased.

In conformity with these views, Plouquet found on examination, that the body of a male infant, born dead, and which had not respired, weighed 53040 grains, the lungs inclusive; and that these latter organs alone weighed 792 grains; the proportion of the lungs to the body, in weight, was therefore in this case as 1 to 67. In another infant, under similar cir