The growth characteristics of an ascitic plasmacytoma (MP 5563) terminating by fistulous communication with the blood-stream.

The growth of ascitic mouse plasmacytoma 5563 has been monitored by (51)Cr-RBC dilutions within the peritoneal cavity together with differential cell counts and protein measurements.Following the intraperitoneal transplantation of one million tumour cells, there is a latency period of 4 days, possibly explained as only a 5% survival of the inoculum. This is followed by logarithmic growth from 4 to 8 days with a doubling time of 18 hours, always similar in different animals. Eventually after 8 days and after about 100 million cells an asymptote is reached which is due to a fistula-like communication between blood-stream and peritoneal cavity. This terminal phase (9-10 days) is rapidly followed by death of the mouse.Reliable tumour cell counts can only be achieved between 4 and 8 days.