Blood Platelet Counts in Infants and in Young Children

The first careful studies of the platelets were made by Max Schultze1in 1865, but to Wright2belongs the credit for our present exact knowledge of their origin. He demonstrated the ability of the megakaryocytes to throw pseudopodia into the sinuses of the bone marrow, and produced the present quite generally accepted evidence that these cytoplasmic processes becoming detached from the parent cell are carried in the blood as the platelets. Ledingham,3in 1914, confirmed Wright's findings and demonstrated the existence of the platelets as entities by preparing an antiserum with guinea-pig platelets as antigen, which was capable of destroying the platelets of the same species on parenteral injection. Bedson4not only verified this observation, but showed that the disappearance of the platelets from the blood of the injected guinea-pig is followed by severe purpura. Dyke5states that there can be no doubt the platelets