On 1990 it has been repeated the Gurwitch experiment on the mitogenetic effect due to the self irradiation of the yeast cell. The effect of self irradiation on yeast cell solid culture has been investigated by counting the young gemmae formation in 104 self irradiated samples, as compared with an equal set of control samples. The results of all the performed experiments, within their statistical reliability, give a uniform evidence of the larger rate of gemmation of self irradiated cell in comparison with controls. A simple statistical treatment, based on the binomial distribution in the hypothesis that equal probabilities exist to find a larger number of gemmae either in the self irradiated samples or in the control ones, shows the occurrence of the effect with a reliability of 97.5%. 

In order to better understand the reasons of the controversial results obtained about this effect from different researchers, another experiment, has been carried on yeast liquid culture on 1996. The analysis of the results seems to confirm the previous experiment with a better reliability (99.95 %) and give clear indication that the protocol of the measurements plays a very important role on obtaining the mitogenetic effect. The correspondence between the period of time in which the spontaneous emission has a maximum and the period of time in which the mitogenetic effect takes place induces to establish that the ultraweak photon emission and the mitosis are strictly connected. 

A third experiment has been carried out on 1998, that has shown the existence of cellular communication between optically coupled cultures which are chemically separate. It is characterised by a notable simplicity of execution from the point of view of the preparation of the culture, the procedure and the measurement of biological parameters; the careful experimental design allows a result which is characterised by a high statistical reliability (99.95 %) with a relatively low number of measurements. During the course of the experiment the growth of two cellular cultures of Saccharomyces cerevisiae is measured, these cultures are identical apart from the fact that one was in optical contact with cells from a third culture. The results have shown that the growth of the two different cultures are systematically different. This result suggests that long range non-chemical interactions exist between yeast cells.