The literature dealing with the nature of irradiation disturbances is replete, but there seems to be no established theory on this phenomenon. It is needless to say that the elucidation of this condition requires further, extensive studies from biochemical, histological and functional aspects, because the irradiation disturbances are not by any means a single entity. Yamamoto of our laboratory states that the compound-phospholipids extracted from tissues of the rabbits exposed to total body irradiation possesses hemolytic and cytolytic effects similar to the effects of irradiation itself. In view of this, the present experiment was conduced in order to observe what effects such an extract would have on the growth of Ehrlich tumor culture cells (JTC 11, strain maintained in the laboratory of Cancer Institute, Okayama Univ.) These cells were cultured in the media containing the aforementioned phospholipids extract in the concentration of 0.1% or 0.5% , and for the control the phospholipids extracted from non-irradiated rabbits was added to the medium in the same concentration. The percentage of degneration of Ehrlich tumor cells was calculated at intervals of one, 3, and 6 hours after the addition of the extract. Two days after the start of culture, the extract was added to the medium, and its effect on the proliferation of Ehrlich cells was studied on the fourth day of the addition of extract. Similarly, morphological changes of Ehrlich cells were observed by electron microscopy at the intervals of 3, 12, 24 and 48 hours after the addition of the extract. As a result it was found that the phospholipids substance extracted from the irradiated rabbit showed a greater degenerative effect and stronger inhibition on the culture cells as well as it elicited more marked morphological changes than the extract from non irradiated rabbit. From this, it is obvious that the extract of the irradiated rabbit has the effect to inhibit the cell growth and destroy the cells just as has been demonstrated in Part 1, which is similar to the disturbances brought about by irradiation.