268 Chronicles of Science. [April, 



is called " forest wool," or wadding ; the other, an establishment for 

 invahds, where the waters used in the manufacture of this pine wool 

 are employed as cui'ative agents. The manufacture has extended, 

 for there are now factories at Euuda, in the Thiiringer-Wald ; at 

 Yonkoping, in Sweden ; Wagenerger, in Holland ; in j)arts of France, 

 and other places. Two cases of these products were shown at the 

 last Paris and Havre exhibitions, which contained various iUustra- 

 tions, in the shape of wool for stuffing mattresses and other articles 

 of furniture, instead of horse-hair ; vegetable wadding, and hygienic 

 flannel for medical application ; essential oil for rheumatism and skin 

 diseases ; cloth made from the fibre ; articles of dress, such as inner 

 vests, drawers, hose, shirts, coverlets, chest preservers, &c., and other 

 useful applications. In the preparation of the textde material an 

 ethereal oil is produced, which is employed as a curative agent for 

 burning, and as a useful solvent. The hquid remaining Irom the 

 decoction of the leaves is used for medical baths. The membranous 

 substance and refuse are compressed into blocks and used as fuel ; 

 from the resinous matter they contain, suflicient gas is produced for 

 illluminating the factory in which the manufacture is carried on. 



Tlie Structure of the Biatomactous Frustule, — Dr. John Denis 

 JMacdonald, F.Ii.S., of the Eoyal Navy, has published a very ela- 

 borate paper on the composition of the Diatom's shell, and the part 

 it plays in the process of division. He finds the views expressed in 

 the writings of Dr. Wallich (particularly in his paper on Tricera- 

 tium, and on the diatom-valve, in the ' Quarterly Jom'nal of 

 Microscopical Science ') most in accordance with his own independent 

 researches. Dr. Wallich appears to have been the first to set forlli 

 clearly that the middle piece, or " zone," running round between 

 the two large valves of the diatom, consists, while the frustule is 

 intact, of two distinct plates, the one received within the other ; and 

 that the growth of such plates can only take place at the free 

 margins, or those which are not connected with the valves. Dr. 

 JMacdonald shows that by the process of division (valve bemg formed 

 within valve), the resulting diatom will ultimately become reduced 

 to a very small size; and he observes that the species would be 

 indefinitely diminished were it not for the process of conjugation, 

 in which Mr. Thwaites showed that the produced si)orangial 

 frustule was very much larger than the parent cells. This dimi- 

 nution of size is very well illustrated in a diagram representing the 

 progeny of the two valves of a divided Biddulj^hia, and by it the 

 ultimate relations of the dividing frustules are exhibited. 



lieproductive Organs of Lichens. — MM. A. Famitzin and 

 J. Boranetsky have been recently investigating this matter, and 

 are led to conclude that — 



1. Not only algae and fungi, but lichens also, are provided with 

 zoospores. 



