1911.] The Causes and Prevention of Miners' Nystagmus. 13 



1909, 1908,' are given as 1618, 1011, and 460. The great increase should be 

 noted, and I believe it will be maintained for some years. 



The following is the result of a systematic examination of 110 officials 

 (chiefly firemen) : — Nystagmus was found in 35 cases, eight of which were 

 marked ; 11 cases were doubtful ; 64 cases were quite free. The visual acuity 

 was tested in all cases, and even when 6/6 was reached the answers were, 



in many cases, given in a hesitating manner : — 





Nystagmus. 



Doubtful. 



Free. 





35 



11 



64 





42 '3 



39 -8 



37 -1 



Mean years of underground life 



30 



26-4 



21 -9 













14 



5 



48 





21 



6 



14 



Error of refraction — 











8 



1 



4 





8 



2 



4 





1 



1 



4 



Degree of error — 









Less than ID 



12 



2 



4 





5 



2 



8 



Colour of hair — 









Fair 



12 



2 



6 





9 



4 



13 



Dark 



14 



5 



45 



Colour of eyes — 











22 



3 



29 





13 



7 



35 



Cost of the Disease. 



I have exact figures of the amount paid to 425 cases of nystagmus during 

 one year. Taking this figure as a basis then the cost of the 1618 cases in the 

 kingdom would be £31,853 in compensation for one year. That this figure 

 is a reasonable one may be seen from the following table compiled from the 

 Blue books quoted above (10, 11, 12) : — 



Table V. 



Year. 



No. of eases. 





Cost of all industrial 

 diseases. 



Increase. 



1908 

 1909 

 1910 



460 

 1011 

 1618 



per cent. 



120 

 60 



£ 



13,382 

 27,288 

 42,507 



Per cent. 



104 



55 



