276 FORMATION OF SLIME OR GUM BY RH1ZOBIUM LEGUMIXOSARUM, 



Experiment 2 with citrate is an example of the identical 

 behaviour of the three Krai races when citrates, succinates or 

 tartrates were employed in the construction of the medium. We 

 shall see a few other examples, but it may be mentioned that 

 with these races some fifteen experiments were made with various 

 nutrients, and it was found that so long as an organic salt was 

 present the behaviour of the three races was precisely similar. 



The Krai races gave a very small yield with dextrose, so that 

 by using dextrose as a standard the numbers for maltose, saccha- 

 rose and mannit in presence of citrate are very high. According 

 to the phosphate experiment, the races* fall into three groups, con- 

 sisting of — (1) the Lupin race, (2) the Pea and Bean races, and 

 (3) the Robinia and Macrozamia races. In the presence of 

 phosphate, the members of the first group form most slime from 

 levulose, the second from dextrose, while the third are indifferent 

 to five of the nutrients. 



The percentage of dry matter was determined in the Lupin- 

 citrate slimes. It varied from 2T % (saccharose) to 4*5 % (dex- 

 trose). The maltose and mannit slimes contained 2-5 %, levu- 

 lose 37 %, and glycerin 2-2 °/ . With the exception of glycerin, 

 the slimes with the smallest yield contained the most solid matter, 

 but this did not influence the relative effects of the nutrients tO' 

 any appreciable extent. 



Until the experiments with phosphate were made, the beha- 

 viour of the Lupin (Krai) race in producing a luxuriant slime 

 upon a levulose or glycerin medium containing an extract of 

 either meat, yeast, turnip or potato, could not be explained. It 

 afterwards became clear that the high yield of slime with levulose 



* With regard to the origin of these races, the Macrozamia race, as 

 already mentioned, occurred in the gum exuding from Macrozamia spiralis, 

 the Krai races, sometimes indicated by "(K)", came from Krai of Prague. 

 Pea (March) and the French Bean races were isolated from the nodules of 

 Pisum sativum and Phaseolus vulgaris, forwarded from the Hawkesbury 

 Agricultural College by Mr. H. W. Potts in March, 1905. The Robinia 

 races were obtained from nodules of Robinia pseudacacia sent from the same 

 place in May, and the Pea (Oct.) and Black Tare from Pisum sativum and 

 Vicia sativa sent in October. 



