ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
291 
from this position. The displaced elements have their terminal expan- 
sions, whether peripheral or central, more or less modified or atrophied. 
Even in the white matter of the brain these spider-cells or astrocytes 
may be found, and in the cerebellum and medulla as well as in the 
fore-brain. Their distribution suggests an isolating or insulating role, 
j>reventing useless contacts between the nervous elements. 
Supra-Renal Capsules of Teleostei.* — Messrs. B. Moore and Swale 
Vincent have continued their investigation of these bodies. The known 
supra-renal bodies of Teleosts resemble anatomically and histologically 
the inter-renal of Elasmobranchs and the cortical portion of the supra- 
renal capsules of higher Vertebrates. An extract made from them does 
not contain the physiologically active principle characteristic of supra- 
renal medulla, nor the characteristic chromogen. The same is true 
of the lymphoid head-kidney. Removal of the cortical gland of eels 
showed that the organ was not absolutely essential to the life of the 
animal. One survived 28 days, another 64, and a third was killed on the 
119th day. 
c. General. 
Means of Defence among Animals.f — L. Cuenot, in an address 
delivered before the Zoological Society of France, gives a graphic and 
popular account of the means of defence among animals. He classifies 
these means of defence, and gives some examples under each heading. 
He describes first those animals which save themselves by flight and by 
autotomy ; those which are protected by a coat of mail, whether formed 
by an exoskeleton or by a calcareous envelope, as in molluscs, or borrowed 
entire, as in the case of the hermit-crab, or constructed of materials 
taken from the outside world, as in many tube-making larvae. Here too 
are included those animals which are defended by spines, passively like 
the porcupine or hedgehog, or actively as in TJromasiix. Electric fishes 
are next treated of, and then follow those which are defended by a chemical 
product, from the simply adhesive mucus of the snail and the acrid se- 
cretion of the toad to the sting of the bee, the poison of the snake, and 
the nauseous fluid ejected by the skunk. Animals which feign death, 
which assume terrifying attitudes, and whose colour harmonises with 
their environment ; mimicry, commensalism, and the setting apart of 
special individuals for the defence of a colony, are all discussed, and the 
lecture ends with a brief account of how some of these means of defence 
may have been acquired, and a note on the necessity for very precise and 
critical experiment to obviate the danger of estimating their value from 
the point of view of human instead of animal sensations and apprecia- 
tions. 
Instinct and Intelligence.* — Prof. C. Emery criticises Wasmann’s 
position. Unlike Wasmann, he thinks it very probable that animals 
form general and abstract ideas. Many of their activities not only show 
the adaptation of means to ends, but conscious purposefulness. It is the 
power of speech which gives distinctiveness to man’s position ; it is at 
once a product of reason and a factor in its development. 
* Prcc. Roy. Soc. London, lxii. (1898) pp. 352-6. 
t Bull. Soc. Zool. France, xxiii. (1898) pp. 37-58 (6 figs.). 
X Biol. Centralbl., xviii. (1898) pp. 17-21. 
