30 THE ORCHID REVIEW. ([Fepruary, 1918, 
in the tubes, as desired. When cold it formsa jelly suitable for the growth 
of the fungi. | 
In order to isolate the fungus, suitable portions of healthy root must be 
chosen. In the case of terrestrial Orchids, a portion cut from near the 
apex of any root is usually suitable. In the case of tropical epiphytes, | 
however, where the distribution of the fungus in the roots is less general, — 
only young roots should be selected. The selected piece of root is washed _ 
thoroughly to remove all traces of dirt, &c., and finally rinsed in distilled — 
water. A clean surface is cut with a sterilised knife. Burgeff describes 
two methods of removing a sterile piece of root for inclusion in a culture. 
One is to take out a tiny cylinder of tissue by means of a specially prepared 
capillary glass tube, in the manner in which soil-borings are taken. The 
sterilised tube with its contents can be introduced into the prepared — 
culture-tube, and the cylinder of tissue pushed down into the medium by 
means of a glass thread. In this way there is little risk of contamination. 
Another method is to cut longitudinal sections of the root with a sterilised 
knife, rejecting the outer surfaces, and place them in a drop of sterilised 
water on a clean object-glass. Examine quickly under the microscope to 
see if the fungus is present. If so, cut away carefully the outer epidermis, — 
and transfer the sections to the prepared sterilised medium. 7 
If successful, fungus hyphe should appear in about two days, and in 
about eight to fourteen days some of the marginal hyphe can be trans: | 
ferred to fresh culture tubes for making stock cultures. : 
It now remains to sow the seeds, which should be done under aseptic | 
conditions. Everything being in readiness the seed 
capsule is opened anda ~ 
number of seeds removed with a sterilised knife 
which they should be treated precisely 
Two questions are invariably rais 
one being whether it is necessary t 
the other whether the nutrient medj 
as other seedlings. a 
- Noel Bernard in an article in out 7 
own pages (O.R., xiv. pp. 201-203, with fig.), 
admitted that some cultivators could get the see 
he attributed this to the prescnce of suitable 
Taking Odontoglossum, he | 
ds to germinate easily, but 
fungi in the houses, for he 
