[Trial of experimental induction of cerebral metastasis in the rabbit carrying a VX2 tumor]. 
Numerous factors remain unknown as far as the mechanism of induction of cerebral metastases is concerned.  Where as of cancer give metastases more readily than others, especially cerebral metastases, the neoplastic embolus can be either eliminated or remain in place in a state of quiescence.  What is the role played by the blood brain barrier from a pathophysiological point of view?  Is there a mechanism which prevents central nervous system metastases?  What is the importance of individual variation?  We attempted to induce cerebral metastases in VX2 carcinoma carrying rabbits to look for an approach to these problems and to create an experimental model of cerebral metastase.  The VX2 carcinoma is easily transplantable and its biological characteristics are well known.  The VX2 tumor is implanted in the thigh of the rabbits and is used in the experimentation starting two weeks following the take of the graft; the tumor is surgically resected and a solution containing approximatively 50,000 tumor cells for 0,1 ml is prepared.  This solution is inoculated via the carotid artery to the same rabbit or to another rabbit of the same breed either or intrathecal way into the brain.  Death occurred 6 to 20 days later and was followed by a complete pathological survey.  The results were the following: --The inoculation via the carotid artery, even with very highly concentrated solution was never followed by any recognizable brain metastasis.  --The inoculation intrathecaly produced only extraparenchymatous metastases where as the direct intracerebral inoculation was followed by the occurence of intracerebral metastases.