Pneumonia and pleurisy were the primary diseases for which venesection was an approved remedy.[79] It had long been believed by bloodletters that these complaints were especially amenable to an early and repeated application of the lancet.[80] Austin Flint had explained in 1867 that bloodletting "is perhaps more applicable to the treatment of inflammation affecting the pulmonary organs than to the treatment of other inflammatory affections, in consequence of the relations of the former [pulmonary organs] to the circulation."[81] Thus, while bloodletting for other diseases declined throughout the nineteenth century, it continued to be advocated for treating apoplexy, pneumonia, and pulmonary edema.[82] The merit of phlebotomy for those afflicted with congestive heart failure was emphasized again in 1912 by H. A. Christian. This condition led to engorgement of the lungs and liver and increased pressure in the venous side of the circulation. Articles advocating bloodletting continued into the 1920s and 1930s.[83] Bloodletting is currently being tested as a treatment for those suffering from angina or heart attacks. Blood is removed on a scheduled basis to maintain the hematocrit (the percentage of red blood cells in the blood) at a specified level. Keeping the hematocrit low has provided relief to those being tested.[84] Other benefits of removing blood, including the lowering of blood pressure, can be obtained by the use of antihypertensive drugs. Thus the valid indications for bleeding are being supplanted by the use of modern drugs that accomplish the same end. By the twentieth century the lancet was replaced in some quarters by safer devices for removing blood and injecting fluids into the bloodstream. Heinrich Stern improved Strauss's special hyperdermic needle. In 1905 Stern designed a venepuncture or aspirating needle that was 7 cm long with a silver cannula of 4 cm. Attached to the handle was a thumb-rest and a tube for removing or adding fluids and a perforator within the cannula. He recommended that the forearm be strapped above the elbow and that the instrument be thrust into the most prominent vein. This streamlined vein puncturing implement reduced the possibility of injecting air and bacteria into the blood.[85] It was, and continues to be, used to withdraw blood for study in the laboratory, to aid in diagnosis of disease, and to collect blood for transfusing into those who need additional blood during an operation or to replace blood lost in an accident or disease. The blood is collected in a glass or plastic graduated container and stored under refrigeration. The study of blood donors has, incidentally, given insights into the physiology of bloodletting since the volume customarily removed from a donor is about the same in volume as that taken by a bleeder (one pint or 500 cc).[86]