Holmgren wool test (of colour vision)

Historical Significance: Alarik Frithiof Holmgren (1831-1897) was a Swedish physiologist who trained with von Brucke in Vienna and Helmholtz in Heidelberg. He was professor of physiology at Upsala, Sweden, from 1864. He researched the ERG but is best remembered for his studies of colour vision and colour blindness and railway and maritime colour vision standards. His investigations were initiated by a railway accident at Lagerlunda in Sweden in April 1876 which he believed was due to colour blindness of the engine-driver, although it is doubtful if this is true . Holmgren surveyed 266 employees on the Uppsala-Gavle railway line and found 13 who were colour-blind. He was a vigorous advocate, lecturing on the dangers of DCV in USA and Europe and in 1877 colour tests had been prescribed for railway and shipping personnel in Sweden. See http://www.whonamedit.com/doctor.cfm/2202.html and Vingrys AJ, Cole BL Origins of colour vision standards Ophthal Physiol Optics 1986, 6, 369. This test was used by the British Board of Trade to test the colour vision of seafarers from 1895 to 1913 and by some railway companies. There are variations on it, namely the Holmgren-Thomson test, Olivers' worsted test, Thomson's Stick, Donders' Wool Test. See Jennings Color-Vision and Color-Blindness: Practical Manual for Railroad Surgeons 1905 Cat # 66. Instructions for use of the test can be found in Swanzy Handbook of Diseases of the Eye 1897. (see Cat No 625). There are many versions of the test and although it was devised in 1877 or thereabout, this version may have been made in the early 20th C. See Cat No 624 for another example.