ZOOLOGY AND EOTANY, MICROSCOPY, ETC. 731 



effected by lon^itucliual division of the fibres already 2)reseiit, and that 

 ajjpears to be henceforward the only method. 



Fundamental Structure of Osseous Tissue.*- M. O. Van der Stricht 

 has examined the fimdaiuental structure of osseous tissue. He finds 

 tliat it i^resents great analogies to hyaline cartilage so far as its texture 

 and the arrangement of its histological elements are concerned. In 

 cartilage tlie fibrils have a tendency to form plexuses, and this tendency 

 is seen in the typical adult osseous tissue of long bones, at least in the 

 peripheral and complemental lamellfe ; it is less pronounced in the 

 circummeduUary lamellfe and in the Haversian systems ; the tendency 

 exists, in a pronounced form, in the tissue of the foetal jierichondiial bone 

 and in that which enters into the composition of the cochlea. 



In this last the fibrils and bundles of fibrils are grouped in such a 

 way as to form a very finely fibrillated osseous substance surrounding 

 the Haversian canals, while others form an alveolar system which is 

 continuous across a wide extent of bone. The fibres and bundles of 

 fibrils are very closely connected with the bone-cells, and are, so far, 

 comparable to the intercajisular bundles of hyaline cartilage. These 

 close relations are to be explained by the mode of origin of the osseous 

 tissue ; in its formation two kinds of cells prol ably take part ; " fibrillo- 

 genous" connective cells giving rise to the fibrils, and osteoblasts to the 

 calcareous deposits. 



Structure of Protoplasm. f — Pj of. O. Biitschli sums up his conclusions 

 as to the vacuolar constitution of j'rotoplasm which he has repeatedy 

 emphasized in regard to Amoehee, Noctiluca, murine Ehizopods, and 

 Ciliata. He has mimicked this structure by a fine emulsion of soap 

 with benzin and xyLd. The vacuolar fnam which results is very stable, 

 remaining in one case unaltered for two months. ' Again, acting i n a 

 suggestion due to Quincke, he sought for fine foam which would remain 

 persistent in water or aqueous solutions. He reduced sugar or salt to 

 the finest i)Owder, mixed it with some drojjs of old olive oil, and watched 

 under a Microscope the behaviour of drops of the mixture when immersed 

 in water. The water diffused into the oil, attracted by the crystal 

 particles, and changed these into minute vacuoles of salt or sugar 

 solution. In twenty-four hours the drops became milky white, and a 

 fine vacuolar structure resulted ; they were cle-ired with glycerin and 

 studied. The optical appearance of a network, of knots, of granulations, 

 of microsoraata indeed was clearly exhibited. Moreover a fine limiting 

 membrane, like that of many cells, was formed. Still better results were 

 obtained by using finely pulverized potassium carbonate mixed with oil. 

 The slight evolution of carbonic acid gas from the free fat acid aided in 

 the process, and the mimic cells when slightly jiressed showed streaming 

 movements like those of Amceba Umax or Pelomyxa ; in one case the 

 streaming lasted twenty-four hours, and after forty-eight hours was 

 restored by increase^l temperature. Biitschli explains the physics of 

 this interesting phenomenon, and emphasizes his conviction that such 

 artificial cells really shed much light alike on the structure and behaviour 

 of real organisms. 



* Arch, de Biol , ix. (1SS9) pp. 27-53 (2 pis.). 



t Verb. Nat.-Med. Ver. Heidelberg, iv. (1889) pp. 12. 



