FRESH FACTS. 



Nineteen Days without a Head. Charles Janet. — " Reaction alcaline 

 des chambres et galeries des nids de Fourmis. Duree de la vie des Fourmis 

 decapitees " (Comptes Rendus Ac. Sci. Paris, 1898, cxxvii. pp. 130-133). Janet 

 had decapitated some workers of Formica rufa in his search for the little Nema- 

 tode worms {Rfiabditis), which are parasitic in the head, and was struck by the 

 vitality of the headless bodies. In a moist chamber they all remained alive for 

 several days, and moved their limbs when gently stimulated. Three lived for 

 two days, one for three, two for five, one for seven, two for nine, and one for 

 nineteen. The last was a large worker, with an abdomen distended with food. 



Uses of the Swim-Bladder. Chr. Jacobs. — " Ueber die Schwimmblase 

 der Fische" {Tubingen Zool. Arb., 1898, iii. pp. 385-411). The swim-bladder 

 of the eel contains 44'74 per cent of oxygen, 51 "97 per cent of nitrogen, 3*29 

 per cent of carbon dioxide, and this mixture is reduced in amount when the eel 

 is kept out of water. The gas is probably liberated by the vascular wall of the 

 air-bladder, and the oxygen is -probably absorbed again by the vascular wall of 

 the pneumatic duct. In pike and perch there seems to be no respiratory 

 function, but the organ probably serves to regulate the specific gravity of the 

 fish. In Cobitis fossilis, which can live in non-aerated water by gulping air at 

 the surface, the small, apparently rudimentary, swim-bladder is enclosed in a 

 bony capsule, and can hardly be supposed to help in breathing. This function 

 seems to be discharged by the thick capillary network beneath the epithelium 

 of the intestine. 



Witch's Milk. S. CI. Tschassownikow. — " Chemische Untersuchung der 

 Hexenmilch " (Le Physiologists Rnsse, 1898, i. pp. 68-72). The milk which is 

 formed by the mammary glands of both sexes soon after birth, attaining its 

 maximum in the third week, and disappearing completely during the next fort- 

 night, has often been examined microscopically, and is well known to contain 

 the same corpuscles as ordinary milk, but it has been analysed only three or 

 four times. The last analysis shows that the component substances are the same 

 as in the milk of normal lactation, but the proportions are different. It con- 

 tains more water and salts, but much less proteid, sugar, and fat. Its propor- 

 tions closely resemble those of asses' milk. 



Making of Muscle. Alex. Meek. — " Preliminary note on the post- 

 embryonal history of striped muscle fibre in Mammals" {Anal. Anzeig., 1898, 

 xiv. pp. 619-621). In the field-mouse, the cat, and the tame rat, hyper- 

 trophy of the fibres occur, accompanied by a reduction in their number, — a 

 good instance of " the struggle of parts within the organism," as Eoux 

 phrased it. 



What is a Brain? J. Steiner. — "Die Funktionen des Centralnerven- 

 systems und ihre Phylogenese," iii. Abth. Die wirbellosen Tiere (Braun- 

 schweig, 1898; see Biol. Centralbl., 1898, xviii. pp. 749-751). The author 



!5° 



