EXTRACTS AND ABSTRACTS FROM FOREIGN JOURNALS. 207 



the space between the yelk and the chorion, or in other words that 

 the thickness of the yelk membrane was increased by the absorption of 

 water. 



He further observes, that every part of the chorion is equally soluble 

 in the caustic alkali, which circumstance may conduce to prove that it 

 is a homogeneous membrane, and not a layer of albumen contained 

 between two membranes, as some have supposed. 



A figure, illustrative of the above described appearance, will be found 

 in Milller's Archives, Tab. II. fig. 7. 



Osckatz on a New Cement or Lute for Microscopic purposes. M. 

 Oschatz recommends, as a cement or lute for glasses containing micro- 

 scopic objects, a composition of sealing wax and whitelead, and for 

 the purpose of keeping apart glasses, so as to prevent injury by their 

 pressure upon delicate objects, rings made of a vegetable pith, such as 

 is afforded by the Helianthus annuus or the Chinese rice-paper. 



M. O. has also invented, but not described, an instrument for cut- 

 ting thin and uniform slices of different substances for microscopic 

 purposes, 



Eschricht on Diceras rude. M. Eschricht, in a letter addressed 

 to Miiller, regrets the publication of a note of his on the so-called 

 Diceras rude, (and which appears in our present volume, p. 153.) He 

 states, that a more attentive examination has caused him to arrive at 

 very different conclusions on the subject. 



The pretended Entozoa correspond in every respect with Sultzer's 

 figures, but the explanation is altogether wrong, as they are in fact only 

 parts of the fruit of Morus nigra or the common mulberry. 



The letter proceeds then to compare the different parts of that fruit 

 with Sultzer's figures, and to point out their close correspondence. 



[From the Comptes Rendus, June, 1842.] 



Gliige on Entozoa in the Vessels of Frogs. M. Gliige has found, 

 in the blood of frogs, an entozoon allied to those which constitute 

 the genus Proteus of Ehrenberg. This animal, the existence of which 

 in the blood of Salmo fario had already been discovered by Valentin, 

 (vide p. 87) appeared to M. Gliige to undergo, in the blood of frogs 

 with which it circulates, metamorphoses similar to those which have al- 

 ready been announced with regard to other Entozoa. 



A second observation of M. Gliige refers to another entozoon, found 

 in great abundance in the lungs of frogs, the Ascaris nigrovenosus. 

 M. Gliige considers that the organ, whose situation is indicated exter- 

 nally by a black line, and which has hitherto been looked upon as the 

 intestine, is in fact the ovary, and in it ova may be distinguished in 

 different states of development, sometimes even containing an embryo 

 coiled up. He has also observed the ova of this entozoon in the lungs 

 of frogs, in which the adult animal was not present ; and thence con- 



