THE HEDGEHOG OR URCHIN 55 



in Charles Waterton's park at Walton Hall (^Zoologist, 1866, 195 ; see 

 also " Tye (Horsham) " = Bainbridge, Field, i6th August 1862, 161) 

 are stated to have been nearly full grown ; their mother was of normal 

 coloration. In one case a hedgehog having white spines was dissected, 

 when the nerves connected with the subcutaneous muscles were stated 

 to have been much diseased (Harper, Zoologist, 185 1, 3022-3023). 



Geographical variation manifests itself in colour, and, as 

 regards the skull, in the shape of the frontal processes of the 

 premaxillae. My conclusions on the latter point have, however, 

 as has been stated above, been disputed by Lonnberg ; but it 

 should be remembered that they were true for the series of 

 specimens at that time in the British Museum, and they may be 

 reinstated when a really satisfactory series becomes available for 

 examination. Southern specimens tend to become white, the extreme 

 being represented by my E. e. hispanicus of south Spain, a 

 form with inconspicuous frontal processes to the premaxillae. My 

 E. e. italicus of Italy is not so pale, and in skull agrees with the 

 typical form of Skandinavia, in which the above processes are sharply 

 pointed. My E. e. consolei of Sicily has long thin bristles with 

 broad, white, strongly contrasted, dusky annulations. E. e. concolor 

 (Martin) from Trebizond and Mount Lebanon is externally very similar, 

 but may be distinguished by its smaller teeth and skull. I have not 

 examined E. e. transcancasiciis of Satunin. 



During hibernation some remarkable changes take place in the 

 tissues, as described by Carlier {pp. cit., vide supra, p. 51). That they are 

 all altered in constitution, is shown by their being less readily acted upon 

 by staining agents than when the animal is active. 



At the commencement of hibernation the blood undergoes a 

 profound change, the number of white corpuscles dropping suddenly 

 from about 20,000 or 18,000 to 3000 or even 1000 per cubic millimetre. 

 At this time the white corpuscles seem to invade the connective tissue 

 of the mucous and submucous coats of the intestinal tracts. Their 

 probable function is to devour the bacteria, which, as Bouchard (" Essai 

 d'une theorie de I'infection," Proc. Tenth Medical Congress, Berlin, 1890) 

 has shown, pass from the alimentary canal through the tissues into the 

 blood of an animal which is cooled or chilled. Their work is .soon 

 accomplished, and they degenerate and are removed. The blood then 

 slowly but surely acquires its normal proportion of corpuscles. 



The lymph-glands also undergo important changes, probably with 

 a view to cleansing the lymph-stream from impurities tending to 

 accumulate during hibernation. 



A special bilateral organ, the hibernating gland, lobulated in shape 

 and orange-brown in colour, is situated chiefly in the axillary, cervical, 

 and dorsal regions. Apart from differences due to age or nutrition, it 



