_Intimacy of family contact._—We have been able to discover in a representative number of families in which influenza has occurred, not only what individuals slept in the various rooms of the household, but also what individuals slept in the same bed with influenza cases. We can, therefore, study for the 1920 epidemic three degrees of contact; contact by sleeping with a case of influenza; by sleeping in the same room but a different bed; and general contact by being in the family, but sleeping in another room. For brevity we designate these, “_sleeping_,” “_room_” and “_family_” _contact_. We have established similar information for 1918, after eliminating families in which deaths or births or other additions or losses had occurred during or subsequent to the 1918 pandemic, in which there has been a change of address, in which the cases are so widely separated that we have designated them _unrelated_, and finally, those families in which the information has been insufficient. With the remaining we have assumed that the distribution within the household has been the same in both epidemics. Statistics are available on 1,734 individuals who in 1918 were exposed to a prior case in the family. Of these, 462 developed influenza and 1,272 did not. 26.6 per cent. of exposed individuals in families contracted influenza, without respect to the degree of exposure. ═════════════════╤═════════════════╤═════════════════╤═════════════════ Intimacy of │ Number so │Number infected. │ Per cent. contact. │ exposed. │ │ infected. ─────────────────┼─────────────────┼─────────────────┼───────────────── “Sleeping” │ 360│ 166│ 45.2 “Room” │ 303│ 59│ 19.5 “Family” │ 1,064│ 273│ 22.3 ─────────────────┴─────────────────┴─────────────────┴───────────────── 45.2 per cent. of individuals sleeping with cases of influenza in 1918 contracted the disease; 19.5 per cent. of those sleeping in the same room, but different beds did so; 22.3 per cent. of those living in the same family, but sleeping in other rooms contracted the disease. _Sleeping contact is more productive of influenza than are the less intimate forms._ Throughout this study the fact that there are multiple possible sources of infection both outside and often within the family complicates the picture. The results for 1920 are similar. Here, 30.0 per cent. of all individuals sleeping with cases of influenza contracted the disease, 17.7 per cent. of room exposures contracted it, while but 11.5 per cent. of family exposures were attacked. Four hundred and sixty-three or 29.1 per cent. of the total of 2,193 individuals exposed in 1920 had had the disease in the 1918 pandemic. Did they show by reason of any immunity a lower attack rate for the same degree of exposure than other individuals in 1920?