The coccobacillus of Bordet and Gengou (Haemophilus pertussis) has now been accepted quite universally as the sole causative factor of whooping cough; a filtrable virus plays no role. This pathogen, first isolated with difficulty from the coughed up, glistening pearls of mucus, can now be recovered with relative ease on cough plates exposed during the catarrhal stage. With the proper technic it has been recovered post mortem from alveoli and bronchi. It is not found in any other respiratory disease; intimately exposed immune subjects rarely harbor it.
EXPERIMENTAL WHOOPING COUGH
Various groups of investigators have produced clinical whooping cough in young monkeys (ringtails, rhesus, chimpanzees) by nasal or intratracheal inoculation of recently isolated cultures. Furthermore, the paroxysmal cough, lymphocytosis and pathologic lesions were produced in monkeys inoculated with bacilli recovered from the finer bronchi of experimentally infected monkeys. To exclude any virus factor, Shibley1 inoculated chimpanzees with a culture