EDITORIAL GLEANINGS. 315 



go on in it ; we are also familiar with the production of kinetic energy 

 when a muscle contracts under a nervous stimulus ; and we are also 

 aware that electric discharges are produced under similar conditions in 

 certain organs of the Torpedo and other fish. The production of light 

 is a phenomenon of the same kind. When we can explain how stimu- 

 lation applied to a nerve causes contraction in a muscle, then, and not 

 till then (so far as I can see), shall we be within reasonable distance of 

 explaining the action of these living lamps. 



" One point is worthy of notice, which has been ascertained, not by 

 experiments on the Cephalopoda but on other animals, namely, the 

 remarkable economy of this illuminant. A perfectly infinitesimal pro- 

 portion of the energy expended is wasted on the production of heat. 

 From this point of view animal phosphorescence puts to shame our 

 most modern devices. Whether we shall ever be able to rival Nature 

 in this respect remains to be seen." 



" The Thickness of the Skull in Mammalia " was the title of a 

 paper read by Prof. Eich. J. Anderson : — " Light shines through the 

 orbital roofs in the young Chimpanzee. The coronal and sagittal 

 regions are opaque. The occipital fossaa and roof and sides of the skull 

 are translucent in the Ox. The Kangaroo and Camel have each trans- 

 lucent roof and sides of skull (except in region of horns), so has the 

 Seal. The parietal in part is translucent m both Manattee and 

 Dugong. The upper surface of the skull in Dogs is not so translucent 

 as the sides. The Dolphin's skull is opaque above and translucent 

 behind, and at the central part of sides. The proliferation of the bone 

 cells along muscle attached appears to co-exist with the diminution of 

 the bone under brain and muscle pressure. The bone cells, like 

 leucocytes, desire to avoid the centres of turbulent activity. The skull 

 of the Porcupine is translucent over the frontal and parietal ; the 

 Capybara has a skull that is translucent on each side of the middle 

 line in front of the roof, and also at the posterior part of the roof, where 

 the translucency is strictly limited to the upper surface. It is some- 

 times stated that the portions of the skull covered by muscle (or ' pro- 

 tected') are thin. The suggestion is that the skull is strengthened 

 where most exposed. It seems better to refer the thinning to the 

 pressure of muscle mass, brain, or organ. The ridges are due to the 

 accumulation of bone-forming tissue at the points of origin and in- 

 sertion of the muscles in question. The skull does not appear to lose, 

 but to gain, in strength by the groining (J. Hunter and Holden). The 

 osteoblasts, like leucocytes, seem to avoid the places where thrills or 

 shocks are most common. The former have greatest freedom outside 



