In these groups special hygienic measures were taken against infection. Furthermore repeated attempts were made to transmit the eye disease by using sterile threads, passing them carefully over the edges of the sore lids and then carefully inoculating the eyes of other rats. These attempts resulted negatively in all cases where the inoculated rats had plenty of the "A" vitamine. Treatment of advanced cases of sore eyes with a saturated solution of boric acid and also with a silver protein solution failed to relieve the condition while as little as 2 per cent of an extract containing the "A" vitamine when added to the ration, speedily resulted in cure and increase of weight. These results combined with similar data compiled by Osborne and Mendel seem to refute Bulley's contentions and to justify our acceptance of xeropthalmia as a specific vitamine deficiency disease. _Osborne and Mendel data_ Total No. No. with eye symptoms Rats on diets deficient in A vitamine . . . . . . . . 136 69 " on diets " " B " . . . . . . . . 225 0 " on diets otherwise deficient . . . . . . . . . 90 0 " on " experimental but probably adequate . 201 0 " on mixed food . . . . . . . . . . . . . . . . 348 0 ____ __ Totals . . . . . . . . . . . . . . . . . . . . . 1000 69 On the other hand all workers know that rats often do develop and grow well for a considerable period of time on a diet free from the "A" and without manifesting the eye disease. The British authorities explain this by assuming that animals have the power to lay down a reserve of this vitamine on which they can draw in emergency. Sherman and his coworkers confirm this power to store the vitamine. Others have been led to explain their results as due to contamination of the basal diet. Daniels and Loughlin recently maintained that the commercial lard used in basal diets and assumed to be "A" vitamine-free was supplied with sufficient of the "A" to produce growth and prevent eye disease. Their views have failed of confirmation by Osborne and Mendel. It is evident therefore that these occasional lapses from specific response to absence of the "A" vitamine need further elucidation. It is equally manifest that in the majority of cases the absence of the "A" will result in both stunted growth and xeropthalmia. The appearance of the eye disease may be taken however, as a sure indication of the absence or deficiency in the "A" vitamine. V. PHYSIOLOGICAL PROPERTIES OF THE "B" VITAMINE