SECTION IV.. An Intensive Study of the Spread of Influenza in Small Groups of

AN INTENSIVE STUDY OF THE SPREAD OF INFLUENZA IN SMALL GROUPS OF CLOSELY ASSOCIATED INDIVIDUALS 175

Effect of overcrowding 179

Domestic cleanliness 187

Economic status 189

Distribution of the disease through the household 191

The first case in the family 194

Intimacy of family contact 197

Recurrent cases 198