156 Chronicles of Science. [Jan., 



■which he called Hyalonema horeaJe — but which should not be put 

 in the genus Hyalonema— that the long tuft of glassy fibres con- 

 stituting the so-called axis of Htjalonema is the pedicle by which 

 it is fixed in the sea -bottom, and that the sponge grows on the top 

 of this. Professor Perceval Wright, of DubHn, went last October to 

 Lisbon for the purpose of dredging the European Glass-rope, dis- 

 covered some two years since by Professor Barboza de Bocage, and 

 he has succeeded m bringing it up from the deep sea-valley in 

 which it grows in such a condition as to leave no doubt in his 

 mind that it hves with the axis inserted in mud, as a sort of stalk. 

 Dr. Carpenter and Professor Wyville Thompson too, on a recent 

 dredging expedition off the west of Ireland, have brought up 

 Hyalonema in the same way. Dr. Wright has no doubt that 

 Max Schultze is right about the parasitic nature of the coral, 

 which sometimes encrusts the axis of Hylomena, which is a true 

 sponge. Dr. Grray, however, retains his opinion that the axis is the 

 work of the coral, and that the sponge on the end of it is parasitic. 

 In a recent article on a form of sponge allied to Euplectella (the 

 beautiful crab's-nest sponge), which is really a close ally of Hyalo- 

 nema, Dr. Gray points out that the long spicules in that form 

 may possibly have been inserted in the mud as a support — as in 

 Hyalonema, yet he still regards the one as sponge, the other as 

 coral. 



Physiology. 



Intellectual Worh and the Temferature of the Head. — Dr. J, 

 S. Lombard, by means of an exceedingly delicate thermo-electric 

 apparatus, has made some highly interesting experiments on the 

 influence of cerebral activity on the temperature of the head. He 

 finds : 1st. That in the state of cerebral repose (during night) the 

 temperature of the head varies very rapidly and frequently. 2nd. 

 The changes are very small, scarcely reaching the hundredth of a 

 degree centigrade. 3rd. In proportion as the activity of the brain 

 increases, the temperature is found to rise. 4th. Any cause attract- 

 ing the attention (a sound, the sight of an object or a person) 

 produces an elevation of temperature. 5th. Very active intellectual 

 work produces a much more marked elevation of temperature than 

 in the preceding cases. It docs not, however, exceed a twentieth 

 of a degree centigrade. 6th. An emotion, or reading aloud of any- 

 thing of great interest, causes an elevation of temperature. It is 

 not the movement of the heart or of the muscles which under 

 these circumstances causes a rise in the temperature of the head. 

 7th. During very arduous intellectual work, the temperature of the 

 limbs falls even as much as a quarter or half a degree centigrade ; in 



