The Retainer Shares shall vest over a four (4) year period, with Retainer Shares representing 10,000,000 shares of Vitro Common Stock vesting upon the execution hereof and with the balance vesting, at a rate of 1/48 th of the total number Retainer Shares not vested upon the execution hereof, per month.  All Retainer Shares which have vested (the “ Vested Shares ” ) shall not be subject to the provision of Section 5(c) below.  Notwithstanding anything to the contrary contained in this Section 4, all unvested Retainer Shares shall immediately be deemed to be vested in the event that there shall be: (a) a merger, consolidation or other reorganization of Vitro unless securities representing more than fifty percent (50%) of the total combined voting power of the voting securities of the successor corporation are immediately thereafter beneficially owned, directly or indirectly and in substantially the same proportion, by the persons who beneficially owned Vitro outstanding voting securities immediately prior to such transaction, or (b) the sale, transfer or other disposition of all or substantially all of Vitro assets, (c) the acquisition, directly or indirectly by any person or related group of persons of securities possessing more than fifty percent (50%) of the total combined voting power of Vitro ’ s outstanding securities other than in connection with the financing of the Lab, or (d) Vitro shall terminate this Agreement other than For Cause, as defined below.