EXTRACTS AND ABSTRACTS FROM FOREIGN JOURNALS. 157 



brain, of the conjunctiva, of all mucous membranes, intestinal villosi- 

 ties, &c. The capillaries thus injected by the chromate of lead are 

 more filled, especially after drying, than by the injections of size, but less 

 than by those of varnish (vernis) ; there also remains some doubt in my 

 mind relative to the actual diameter of the latter canals. Those which 

 run parallel to each primitive muscular fasciculus, to the number of four 

 or six, appeared to me to possess, in the dog, ^^th or ^-oth of a milli- 

 metre ; but it is possible that their dimensions had been reduced by the 

 action of one or the other of the two solutions employed, or that they 

 had not been sufficiently filled. I am now engaged in determining the 

 relation which exists between the size of injected vessels, and their size 

 during life. 



Bowman on the Contraction of Voluntary Muscles. At the sitting of 

 the Academy of Sciences, 27th September, 1841, Mr. J. E. Bowman, 

 Demonstrator of Anatomy, King's College, London, stated, that he had 

 sufficiently proved, that contraction never takes place in the whole 

 length of a primitive fasciculus at the same instant, but that even the 

 most violent contraction consists of partial contractions, which change 

 their place with an inconceivable quickness. 



Researches on the Reddening of Waters, and their Oxygenation by Ani- 

 malcules and Alga. MM. C. and A. Morren are of opinion that the 

 oxygen of the air in water varies in quantity at different hours of the 

 day. For example : in very sultry (insolation) days, the quan- 

 tity of oxygen in the morning is 24 parts in 100 ; at mid-day, 48 parts 

 in 100; and at five o'clock, from 60 to even 61 parts in 100. This 

 effect is in relation with the respiration of animalcules, and aquatic 

 Algse. Among the bodies which produce this effect, there is an ani- 

 malcule which the authors have made their particular study, and to 

 which the name of Discerea purpurea has been given. It is one of a 

 number which colour water red. The same authors have further ex- 

 amined the phenomenon attendant on the red colour of waters, and 

 have enumerated forty- two plants and animals which redden liquids. 

 They have particularly noticed the Monas vinosa of Ehrenberg, the 

 Monas rosea r the Trachelemonas volvocina, the Euglena sanguinea, the 

 H&matococcus, and the Tessararthra, of which they have given mono- 

 graphs. According to these observers, the famed Protococcus nivalis of 

 the snow is an animal. 30^ August, 1841. 



M. Soleil presented a Microscope of M. Donne, to which he had 

 added an Adjusting Screw, rendering it much more handy and useful. 

 July 19, 1841. 



Laurent on colouring Hydra. He has succeeded in colouring the 

 Hydra blue, white, and red, by feeding them with indigo, chalk, or car- 

 mine ; but he remarked that the eggs did not partake of the colouring, 

 although the parent acquired a very vivid tint. Guerin's Rev. Zool., 

 June 1841, p. 204. 



Turpin on the Acarus of Pears. Under the epidermis of the fruit of 



