88 REPORT—1848. 
fervoid filaments originating from the sporules are another form of gemmation in the 
mosses ; and gemmation also takes place in the perfect state of the plant in Bryum 
androgynum and other species. In the Lichens and Hepatice there is also exhibited a 
great tendency to produce gemme. If the opinion now advanced with reference to 
gemmation be the correct one, it follows that in some species of mosses, such as 
Encalypta streptocarpa, and of lichens, as Parmelia physodes, in which true repro- 
duction by means of spores seems scarcely ever to take place in some localities, an 
individual plant, by means of its gemmez or offsets, may attain the age of our largest 
trees, and occupy as large a space in the economy of nature. The tendency to pro- 
duce gemmz in the lower tribes of plants seems to warrant our considering that 
what has been described by authors as a second form of fructification in some of the 
Algz, should be rather referred to gemmation : for example,—the tetraspores of the 
Floridee, the Opseospermata of Draparnaldia and Chetophora, and what has been 
described by Thuret as the spore of Vaucheria, The author took occasion to observe 
that he did not consider the cilia with which the last-named organ is furnished, as 
affording any proof of a higher character of organization than if no such cilia existed, 
and he was inclined to believe that these appendages are merely a modification of 
cell-membrane, which latter is probably, judging from its mechanical properties, 
made up of a mass of such delicate filaments as those forming the cilia. 
On a supposed connexion between an insufficient Use of Salt in Food and the 
Progress of Asiatic Cholera. By W. HH. Croox, LL.D. 
In this communication the author surveyed the geographical and social position of 
the district in which this kind of cholera originates, and inferred that in that district 
the use of salt, as an article of daily consumption, was (by artificial arrangements) 
limited to an amount far below that which the healthy and vigorous sustentation of 
the functions of life requires. He then examined the relation of fatality and preva- 
lence of cholera in different countries of Europe to the price and consumption of salt, 
and infers as not improbable that a deficient quantity of salt in the food of a nation 
may predispose many of its inhabitants to receive and generate the virus of cholera, 
or render them less able to resist its attacks. 
——— 
An attempt to give a Physiological Explanation how Persons both Blind, 
Deaf and Dumb from Infancy interpret the Communications of others by 
their Touch only. By Ricuarpv Fow.eEr, M.D., F.R.S. 
The facility with which young blind and deaf persons acquire such efficiency in 
their fingers as to enable them to substitute touch for loss of both sight and hearing, 
admits of a physiological explanation from the following considerations :— 
That the knowledge of objects and their various relations is not from the specific 
nerve of each organ of sense, but from the muscular sense residing in the muscles 
by which they are adjusted. Mere contact without pressure gives no knowledge 
of the forms or bulk of objects, and soon ceases to excite any sensation if the mus- 
cles which move the fingers are not in action. This fact, that all our distinguishing 
sensations are in the muscular sense of adjusting muscles, seems to afford a satisfac- 
tory proof that it is by this objects appear erect, though in the dead eye they are 
inverted when seen on the retina. When the head is unmoved and the eye alone 
raised to look up at the ceiling, we have a contractile feeling in the elevator muscles 
of the eye and forehead, and when we depress our eyes we have analogous feelings 
in the depressing muscles. Such muscular sensations, like those of the larynx, pass 
unheeded by those who can both hear and see, but the slightest sensations indica- 
tive of the meaning of others are objects of anxious attention to the blind and deaf, 
more particularly when new to them. This excitement by novelty of feeling is well 
marked by Sir H. Davy, who said he felt an extended sense of touch when he had 
for some time breathed the nitrous oxide gas, and this probably from the larger pro- 
portion of oxygen than in atmospheric air. For I think it will be found, that simul- 
taneously with retransmission of motor influence to the adjusting muscles of any 
