Scientific .Memoirs. by
to extend peripherally by the formation of distinct islets, which subsequently
become confluent with one another, and with the parent mass. The smell is
strong, sometimes of a somewhat yeasty character, and at others resembling
that of decaying apples. As a rule, it is not easy to transplant from potato to
potato, but I have. had. one series of cultivations in which very thorough accli-
matisation has taken place, and in which successful transfers have now been
carried on for a period of eleven months. As certain remarkable phenomena
have manifested themselves in connection with these, it may be well here to give
some particulars regarding them. The first potato of the series was inocu
- lated on the i oth February 189o, with materials from all Agar-agar tube cultiva-
- t i o n o f t h e s e r i e s p r o p e r t o t h e s p e c i e s . G r o w t h t o o k p l a c e v e r y s l o w l y , s o t h a t
on the 18th February its results consisted only of a single, small, prominent
yellow patch. This was of soft consistence, and the material of which it was
composed, and which was formed of well-formed Commas, was readily diffusible
in salt-solution. Portions of it, transferred to other potatoes, gave origin to
rapidly-spreading, thick, soft yellow growths, one of which was photographed
(vide Plate II, Fig. 2), and from these the continuous series of cultivations still
carried on at the present time, January 1891, was readily propagated. The
cultivations almost from the first ceased to show characteristic Commas, and
consisted of almost micrococcoid particles, short ovals, and varying numbers
of ill-formed Commas. These, in some cases, appeared as though they were com-
- posed of short series of the micrococcoid bodies, and in others as if built up by
the more or less complete union of two of the oval elements. Agar-agar tube-
cultivations derived from them continued for some time invariably and rapidly
to yield abundant and pure growths of characteristic Commas. Towards the
latter part of April, however, it began to be difficult to secure success in' transfer,
and in a series of twelve tubes set on the 15th of May only a single one yielded any
growth. Subsequent to this, during a period of some months, although transfers
from potato to potato were constantly successful and continued to yield charac
-teristic yellow growths, all attempts at transfer from potatoes to Agar-agar
m e d i - u m , o r t o b r o t h , w e r e i n v a r i a b l y u n s u c c e s s f u l . T h e g r o w t h o n p o t a t o e s v a r i e d i n
regard to details in different instances. The color was always yellow, but the
tint varied from ochreous yellow to strong canary, and the consistence also was
not invariably alike, being in some cases quite diffluent, and in others more or
less decidedly adhesive. The tint appeared to be in some degree related to
the precise form prevailing among the elements in the different cases, being
paler where oval and abortive commatous forms predominated, and stronger.
yellow in proportion to the abundance of micrococcoid ones. The form of the
growth also varied, for whilst in the earlier cultivations it was characterised, as
shown
in the photograph, by the presence of a marginal fringe of islets, and by-
an irregular outline resulting from the coalescence of these, for some time it
almost invariably presented itself as a continuous expansion with even edges.
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