406 Miscellanies. 
in general, affected by external agents, much in the same manner as 
the larger organic beings. 12. The microscopic animalcula being 
extremely light, they are elevated by the weakest currents, and often 
earried into the atmosphere. 13. Those observers who think they 
have seen how these minute creatures suddenly spring from inert mat- 
ter, have altogether overlooked their complicated structure. 14. It 
has been found possible to refer to certain limits or organic laws, the 
wonderful and constant changes of form which some of these animal- 
cula present. 15. That the organism of these animalcula is com- 
paratively powerful, is evinced by the strength of their teeth and of 
their apparatus for mastication ; they are also possessed of the same 
mental faculties as other animals. 16. The observation of these mi- 
croscopic beings has led toa more precise definition of what constitutes 
an animal, as distinct from plants, in making us better acquainted with 
the systems of which the latter are destitute—W. W.— Weimar. 
20. Meeting of the British Association for the Advancement of Sci- 
ence.—Just as this No. was closing, we have received the following 
important communications, to which by request, we give immediate in- 
sertion. 
1. Letter from Ropvericx Impey Murcuison, Esq., to Prof. SrLLIMAN. 
London, 16 Belgrave Square, Feb. 24, 1840. 
My dear Professor—I enclose herewith an invitation to attend the 
next meeting of the British Association, to be held at Glasgow on the 
17th of September next. The local authorities of that city, from 
whom this invitation is sent, wish you to be the organ, through your 
y circulated and valuable Journal, of asking any Professors ot 
cultivatere ae science in the different states of N. America, to honor us 
by being present at our next meeting. 
I need hardly tell you who are so well versed in British geology, 
that Glasgow is peculiarly attractive to geologists, and that the Isle 
of Arran alone will afford much instruction in some of the most inter- 
Fahy pages of geological history. 
nior General Secretary of the Association, I can assure you, 
that es greater the number of your countrymen, who may honor the 
meeting with their presence, the higher will be the gratification of the 
officers and council of our body, including yours, very faithfully, 
R . Murcuison. 
2. Circular of the British Association for the Advancement of Sciences 
addressed to the * invited to atiend its next meeting. 
Glasgow, 1st January, 1840. 
Sir—We have the honor to announce, that the next meeting of the 
British Association for the Advancement of Science, takes place in 
