NATURE 



[March io, 1910 



with four or five sudden jerks, then, after one or 

 two minutes' interval, when the mole is collecting 

 more loose earth, another sausage will appear as 

 before, and so on until the work is complete. After the 

 nest-cavity comes the excavation of the bolt-run, and 

 finally, to make all safe and waterproof, the mole 

 piles up a mass of earth, often amounting to a large 

 barrow-load, by means of tunnels around the base of 

 the existing heap. These tunnels sometimes break 

 into one another and sometimes into the nest-cavity, 

 and so cause a labyrinth which has given rise to much 

 erroneous speculation in the past. 



Fig. 3. — Sectional view of the completed fortress, tt, Tunnels formed in 

 piling up earth from outside to make the nest rainproof. 



A fortress is often completed in a single night. The 

 young are not born in the winter " fortress," but in a 

 separate habitation made by the female alone. It is 

 built on the same plan as the "fortress," but usually 

 simpler in construction and without the bolt-run. 

 The female produces only one litter a year, and the 

 young, which are born from the end of April to the 

 end of May, vary in number from two to six. Naked, 

 blind, and pink, they turn ■ lead-colour in ten davs ; 

 after a fortnight a grey velvet pelage is visible, which 

 becomes black at the end of three weeks, when the 

 eyes open. The ears are opened on the seventeenth 



Fig. 4. — The completed fortress viewed from above, with the tunnels t t, 

 &C.', l^d bare. 



day. Attempts to rear the young by hand have 

 hitherto proved futile, for, though they will suck 

 freely from flannel or cotton wool soaked in warm 

 milk, they pine and die on the third or fourth day. 



There has always been much discussion as to the 

 mole's power of sight. Dissection has shown that 

 the size of the eye is greater in the embryo than in 

 the adult, indicating that the sight of the race has 

 deteriorated. From numerous experiments the writer 

 is^ convinced that the adult mole is practically blind. 

 Moles encountered in the day-time have taken no 

 notice of a human being waving a hand close in 

 NO. 2106, VOL. 83] 



front, nor at night do they show signs of conscious- 

 ness of a light waved before their nose; but, if the 

 slightest sound is made, the greatest excitement is 

 instantly shown. The writer has often thrown down 

 worms before a captive mole to test the sight. At 

 once the mole becomes aware of the worm, but the 

 haphazard way in which he will poke about for it with 

 his snout shows clearly that he is guided by scent, 

 and perhaps by hearing, but not by sight. It is true 

 that at the least excitement the fur will radiate round 

 the minute eye, and it has been suggested that the 

 animal thus clears his eye to see; most probably, 

 however, this mechanical action is retained though lia 

 longer of use, since the blind eye cannot benefit 

 thereby. When, after a hurried and blundering 

 search, the worm has been located, the mole holds 

 it down with his fore paws and eats it from end to 

 end with quick, jerky bites. When the animal's 

 immense appetite is at length satisfied and worms are 

 still being supplied, the mole will often give the worm 

 several bites to disable it. and will then cram it into 

 the earth, presumably to bury it for future use — after 

 the manner of the dog with bones and the squirrel 

 with acorns. 



The senses of smell and hearing must be very acute 

 to enable the mole to locate a pheasant's or partridge's 

 nest above his run. That this is the case is testified 



Photo, by 



T. Bellchambers. 

 Fig. 5. — Young moles ready to leave the nest. 



by two gamekeepers in different parts of the countrv, 

 both of whom state that the nests are often entered 

 from below and the eggs eaten. 



It is surprising how soon a captive mole becomes^ 

 indifferent to being handled. Within half an hour of 

 capture it may be stroked and scratched without 

 causing alarrti ; the writer has even suspended one by 

 the tail without causing the animal to cease from 

 lapping water. Of course, gentle handling is neces- 

 sar)^ and avoidance of any sudden or jerky movement. 

 Another mole soon learnt to come out of his nest and 

 look for worms when the writer scratched the side of 

 the packing-case in which the captive dwelt. 



Lionel E. Adams. 



THE SOUNDS OF THE HEART A 



T^HE sounds of the heart have always occupied 

 -*■ the attention of physiologists both as regards 

 their cause and as to their relations in time to other 

 phenomena of the circulation, such as the impulse 

 of the heart on the wall of the chest, and the pulse 

 in arteries and other organs more or less distant 

 from the heart. During the last few years much atten- 

 tion has been paid to these time-relations, and much 



1 Phono-Kardiogramme von I Prof. Otto Weiss. (Jena : Gustav Fischer, 

 igog.y From Prof. E. Gaupp and Prof. W. Nagel's SaDimlung Anatom- 

 ischerund Physzolcgischer Vortrage u}id Au/satze. Heft 7. A full biblio- 

 graphy will be found in Prof. Wtiis's paper. Pp.37. Price 1. 50 marks. 



