He found that the cells emit radiations that stimulate growth and cellular activity in adjacent cells. This emission of radiation is sometimes referred to as Gurwitsch rays.

In 1922, a Russian biophysicist, Alexander Gurwitsch, demonstrated an interesting optical phenomenon associated with cells, a phenomenon he called “mitogenetic radiation.” Gurwitsch showed that adjacent cells could be stimulated to divide optically by endogenous UV radiation generated by cells in optical contact with them. These emissions, sometimes referred to as Gurwitsch rays, have the property of stimulating growth and cellular activity.

Dr. Tom Bearden, a nuclear engineer, has done the research and believes that infrared (IR) Gurwitsch radiation stimulates cellular mitochondria as the sub-cellular target responsible for the subsequent growth phenomena

If you want to read more about Gurwitsch’s work, you can find his papers here and here.