224 RESEARCHES ON FUNGI 



direct distance of 6 cm. shown in Fig. 128. In any case, whatever 

 the actual speed of the movement of the nuclei may have been, we 

 are obhged to regard the calculated average speed of 1-5 mm. per 

 hour for 40 hours as an under-estimate. 



Furthermore, it seems very probable that the travelHng (ab) 

 nuclei did not move along the (AB) hyphae at a uniform speed but 

 paused occasionally, possibly for nuclear division. The greatest 

 speed attained by an {ab) nucleus in passing along an individual 

 {AB) hypha may possibly have been two or three times the calculated 

 average speed of 1 • 5 mm. per hour, i.e. it may have been as much as 

 3 -0-4 -5 mm. per hour. 



(4) Experiment No. 2 .• a haploid mycelium inoculated with a 

 diploid mycelium. In Experiment No. 2 a large haploid mycehum 

 {AB) was inoculated at what we shall again regard as the zero hour 

 with a tiny mass of a diploid mycelium {AB)+{ab) when, as shown 

 in Fig. 129 by a heavier inner circle, it had been growing for nine 

 days and was 6-2 cm. in diameter. The record for this experi- 

 ment, embodied in Fig. 129, is similar to that already described for 

 Experiment No. 1. 



After 42 hours, it was observed that the central haploid mycehum 

 {AB) was becoming diploidised by the diploid mycehum {AB)+{ab) ; 

 for, already, clamp-connexions were to be seen along the periphery 

 of the former proceeding away from the diploid inoculum to a 

 distance of 3-3 cm. on one side and 4-7 cm. on the other side 

 {vide broken lines in Fig. 129). 



After 66 hours, diploidisation of the central haploid mycehum 

 had progressed on one side of the diploid inoculum to a distance of 

 7 -0 cm. and on the other side to a distance of 7 • 7 cm. {vide broken 



lines in Fig. 129). 



We may suppose that, when the haploid mycehum {AB) and 

 the diploid mycehum {AB)-{-{ab) came into contact, hyphal fusions 

 took place between the two myceha and that one or more {ab) 

 nuclei passed out of the diploid mycehum into the haploid mycehum. 

 Some of these nuclei, as the data just recorded indicate, must have 

 travelled through the large central haploid mycehum a distance of 

 7-7 cm. in 66 hours, i.e. at an average speed of 1 • 17 mm. per hour. 

 If, as before, we subtract two hours from the 66 hours to allow for 



