The invention is based in part on the observation that significant portions of porcine livers appear to remain intact after perfusion by standard methods, suggesting that the perfusion procedures employed do not result in complete enzymatic digestion. Recovery of cells is therefore substantially lower than would be possible if the organs were thoroughly digested. It is found that increased perfusion flow rate, occlusion of at least one major blood vessel leading out of the organ, increased enzymatic digestion time, and vigorous tissue dissociation techniques can be combined to afford a uniquely high yield of viable cells.