IN the course of investigations on the intestinal flora of white rats an unusual helically coiled organism was observed on several occasions in gram-stained smears of the caecum contents (Fig.

Techniques for blood collection from the rat include puncture of the heart, retro-orbital plexus, jugular vein, saphenous vein, tail blood vessels, carotid artery, abdominal aorta, and vena cava.