Little Sister Gift

For every three Little Sisters that you rescue, Dr. Bridgette Tenenbaum will leave you a gift at the Gatherer's Garden. Each gift contains 200 ADAM, plus the following items. If you rescue every Little Sister, you will receive the gift at the level shown; otherwise it will occur later, as you rescue every third Little Sister:
 * 1) Neptune's Bounty: Hypnotize Big Daddy plasmid; 12 Armor-piercing Pistol Rounds
 * 2) Arcadia: Safecracker tonic; 12 Electric Buck
 * 3) Fort Frolic: Hypnotize Big Daddy 2 plasmid; 4 First Aid Kits
 * 4) Hephaestus: 4 EVE Hypos; 6 Proximity Mines
 * 5) Olympus Heights: Armored Shell 2 tonic; 12 Incendiary Bolts
 * 6) Apollo Square: Prolific Inventor tonic; 150 Liquid Nitrogen
 * 7) Point Prometheus: 100 Antipersonnel Rounds; 4 First Aid Kits

Players receive 160 ADAM per Little Sister if they Harvest, or 80 if they Rescue. Since Tenenbaum's Gifts appear at every third rescue, you would have had 480 ADAM if you had harvested the three (3x160), but will get 440 ADAM for rescuing them (3x80 + 200). Therefore, each of the above gifts are worth 40 ADAM. And perhaps also worth a clean conscience.

Note that if you Use ("E") a gift, it will disappear the next time it leaves your field of view, even if you were already full of some of the items and thus didn't pick them up from the gift. Therefore, if you see something you like, but aren't ready to recieve it yet - such as if you already have 6 Proximity Mines and would like to use them for a Big Daddy - do not E the gift yet. Lay your mines, then Use the gift. You can also use the above list to plan ahead and, for example, not worry about getting low on EVE Hypos or First Aid Kits if you know they'll be gifted to you soon.

If you rush out of a level before picking up a gift you earned there, it will appear at the Garden on the next level.