Need I say, I was a little bit disappointed.
I hadn't followed the directions. The operator is supposed to use rooting hormones in the water. Then it is recommended to use hydroponic nutrient solution for feeding the plants while they are rooting.
And what is this? It can only be described as a bacterial slime mold.
So, I have planted out the remaining living cuttings, one of which has three or four tiny roots on it, the rest have no visible roots but are not dead or sliming. If these 5 live, then that ratio of 5:8 survival rating is not too bad, considering there is nothing but water in the system.