508 
POPULAR SCIENCE REVIEW. 
flourisliing accounts of the cinchona plantations continue to arrive from 
India. In the Neilgherries, Sir William Denison asserts that though the 
county had in April last suffered from 112 days’ drought, yet the cinchona 
plantations had not been damaged, and that the plants were being propagated 
at the rate of from 30,000 to 40,000 monthly. From Ceylon, Dr. Thwaites 
writes, that in September last he had 190,000 plants, the tallest six feet 
high, that applications had been received for 28,500 plants, of which 9,000 
had been supplied, and that he expected to issue 20,000 monthly. Jamaica 
still needs a proper person to superintend a cinchona plantation. The capa- 
bility of the island for its growth has been abundatly proved by Mr. 
Wilson of the Botanic Garden, who, under every discouragement, has planted 
out 400 plants in a suitable locality, which, however, being at a great distance 
from the botanic gardens require a good, resident, practical gardener for their 
superintendence and increase. 
The Structure of the Vinegar Plant. — Many additions to our knowledge 
of this fungus have been made by Mr. H. J. Slack in his recent paper read 
to the Microscopical Society, and published in its proceedings. An examina- 
tion of the vinegar plant with low powers shows no more than the micro- 
graphic dictionary describes, but if portions are carefully illuminated and 
viewed under a magnification of from one to three thousand linear, it 
wffl be found that the gelatinous matter, hitherto treated as structureless, 
contains millions of small bodies resembling the bacteria that occur in the 
pellicle of solutions set aside to develop infusoria. These bodies vary 
considerably in size, some not exceeding T-Tr-o-Triy of inch in length, others 
twice as big or more. If stained with iodine, they sometimes become a 
little plainer ; but the more delicate will not appear as beaded structures to 
an observer coming quite fresh to their examination. Mr. Slack does not 
consider that all are beaded, and some seem to be in an intermediate state. 
The number that can be made out will depend upon the time employed in 
the investigation, and in the course of a week or two the observer will be 
able to trace their structure to a sufficient extent to justify the belief that 
all either possess or tend toward the bacterium form. Mr. Slack believes 
the yeast plant is commonly associated with bacterium-like bodies, and, 
probably, wffien’ their number is moderate, they do not noticeably interfere 
with the various fermentations. In the vinegar plant they are so numerous 
as to suggest the idea that they play an important part in the complicated 
series of actions which the plant, as a whole, excites. 
The Phenomena of Conjugation in Navicula Serians. — That indefatigable 
observer, Mr. H. T. Carter, describes the method of conjugation of N. serians 
in a late number of the Annals of Natural History. The process is 
divided into a number of stages, which are arranged numerically as follows 
(1.) Two frustules, varying a little in size, approximate themselves. (2.) They 
secrete a gelatinous substance around them, which becomes covered by a 
delicate pellicular membrane. (3.) The sarcodal sacs force open respectively 
their frustules through the fissiperating divisional line, and carrying vdth 
them their contents, now all undistinguishably mixed together, approach each 
other and unite into one spherical mass, called the spore or sporangium. 
(4.) The sporangium divides itself equally into two spherical sporangial cells, 
each of which forms around itself a thick opalescent capsule. (5.) The 
