1. That no amount of pressure, short of entirely destroying the lung tissue, can expel the air from a lung that has been inflated, or from one in which respiration has taken place.
2. Pressure is, therefore, no test of natural respiration or of artificial inflation.
In answer to the above, it will only be necessary to refer to what has been already said with regard to the difficulty of inflation, and the more probable event of the condition of the lungs being the result of respiration.
Casper thus sums up the result of his views with regard to the probative value of the docimasia pulmonaris:
“That a child has certainly lived
during and after its birth—
“1. When the diaphragm stands between the fifth and sixth ribs.
“2. When the lungs more or less completely occupy the thorax, or at least do not require to be sought for by artificial separation of the walls when cut through.
“3. When the ground colour of the lungs is broken by insular marblings.
“4. When the lungs are found by careful experiment to be capable of floating.
“5. When a bloody froth flows from the cut surface of the lung on slight pressure.”