Scientific Inielliyence — Geology. 207 



12. Silk Worms. — The chief manufactiu-es of Milan are silk and iron : 

 of the former there are several establishments, and the culture of the 

 mulberry is in consequence very extensive. Raumer quotes the follow- 

 ing curious fact from Berger's book : — " 24,000 eggs of the silk- worm 

 weigh a quarter of an ounce ; the worm lives from forty-five to fifty- 

 three days ; increases his weight in thirty days 9500 fold, and during 

 the last twenty-eight days of his life eats nothing. For 739 lbs. of 

 mulberry leaves, 70 lbs. of cocoons are obtained ; 100 lbs. of cocoons 

 give 8} lbs. of spun silk ; and one pound of cocoons will produce » 

 single thread of 88,000 fathoms in length." — Barroic's Tour i?i Lom- 

 bard ij, p. 146. 



13. Snail Trade of Vim. — Ulm has not much traffic, the principal 

 exports, as I understood, being snails, which are bred and fattened, and 

 of which many millions are annually sent into Germany and other Ca- 

 tholic countries in Lent, where they are esteemed a great delicacy. — 

 Barrow's Tour in Lombard^, Tyrol, S^x., p. 358. 



14. Notice of a Memoir j lately read before the Royal Societyy on the ulti' 

 mate Distribution of the Air-Passayes, and of the Modes of Forma- 

 tion of the Air- Cells of the Lungs. By William Addison, F. L. S., 

 Surgeon, Great Malvern. 



After reciting the various opinions which have prevailed among ana- 

 tomists regarding the manner in which the bronchial tubes terminate, 

 whether, as some suppose, having free communication with one another, 

 or, as others maintain, by distinct and separate cells having no such 

 intercommunication, the author states that, having been engaged in in- 

 vestigating, with the aid of the microscope, the seat and nature of pul- 

 monary tubercles, he could never discover, in the course of his inquiry, 

 any tubes ending in a cul-de-sac ; but, on the contrary, always saw, 

 in every section that he made, air-cells communicating with each other. 

 He concludes from his experiments and observations, that the bronchial 

 tubes, after dividing dichotomously into a multitude of minute branches, 

 which pursue their course in the cellular interstices of the lobules, ter- 

 minate, in their interior, in branched air-passages, and in air-cells which 

 freely connnunicate with one another, and have a closed termination at 

 the boundary of the lobule. The apertures by which these air-cells 

 open into one another are termed by the author lobular passages ; but 

 he states that the air-cells have not an indiscriminate or general inter- 

 communication throughout the interior of a lobule, and that no anasto- 



