Abstract
Animals in which arteries, veins and ducts of various organs are injected with salts of heavy metals, such as mercury, barium, lead, gold and silver are skiagraphed and subsequently studied in either plane view or by means of stereoscopic rœntgenograms. The method is especially valuable for the study of animals from the view point of comparative anatomy, Such preparations show clearly first, the general construction of the arterial or venous system and secondly the minute ramifications of the respective arteriole systems on and within the organs. Probably the most valuable use that this method has is in the study of developing systems and ducts in embryos. Here the homologies of the embryonic blood vessels and the adult arteries and veins can readily be demonstrated.
Barium sulfate and litharge are the best injection media. Baruim sulfate is prepared by precipitating it from barium hydroxide with ammonium sulfate, the precipitation being done at about 57° C. This gives a very fine flocculent mass that will enter many of the smaller arteries and veins. An aqueous suspension is used. Red lead and litharge are employed in either aqueous suspension or in oil.
The plates are exposed to the x-rays varying lengths of time depending on the size and density of the object and the amount of current used.
The paper is illustrated with lantern slides of the prepared objects.
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