Prognosis and Treatment of Cardiac Infarction

three-year periods of observation there was no evidence of a waning in the degree of protection afforded by the pertussis vaccines.Swabs were taken from 96.4%" of all clinical cases, and in 59.8% a bacteriological confirmation was obtained.Each batch of vaccine gave substantial protection, but the two batches supplied by the Michigan Department of Health gave a considerably greater degree of protection than the others.Vaccines prepared in this country according to the method used by the Michigan Department of Health are now being tested in similar field trials.An investigation is also being made in which the immunizing properties of vaccines as indicated by laboratory tests are being compared with their prophylactic value in the field.The Whooping-cough Immunization Committee and the medical officers of health concerned wish to record their gratitude to the many parents who, in the full knowledge that their children would not necessarily receive pertussis vaccine, consented to take part in the investigation.They also wish to thank Messrs.