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Slide rule: Picker X-ray Fetal Medical, made by K&E Co., [Hoboken], n.d., ca. 1950s-1967.

Object/Artifact
Picker X-ray Fetal Medical slide rule, made by Keuffel & Esser Co., [Hoboken], no date, circa 1950s-1967. Printed, black on white, wood with metal caliper measure; 2-3/4" overall height (stator 1-13/16") x 15" long x 3/8" thick. Improved glass indicator, special, hairline on lower half only. An uncommon slide rule and an example of commissioned work done by K&E where special slide rules were custom made to the customer's specifications. The name of the rule does appear on the item and the one used here is the common name often found for it. Used to measure the size of a fetus head in utero from an x-ray or x-rays made of the mother's pelvic region. The reverse has four reference illustrations, Figures 1 to 4, and text, but it also refers to an instruction booklet which is not present. See notes for transciption of the text on the back. Other names associated with its medical uses: cephalo-pelvitry, x-ray pelvitry. Marked with K&E logo at the right end of slide with "Picker X-Ray" logo to its left. No serial number. Top edge beveled with millimeter rule (25 cm) from left running to fixed caliper blade. Slide had a caliper blade at right end; it could slide to the right a maximum of 4 inches with a stop button on the back side running in a groove on the stator. Scales: A B - B-1, B-2 (short scales) C (short scale) D E As per the text on the back, the hairline intersects only scales B to E. The date is estimated from two points: the indicator style which was used into the 1950s (ones introduced in the later 1950s were plastic) and the name "Picker X-Ray" which was the company name it used until 1967 when it was changed to "Picker Corporation." The indicator style is the less definitive of the two as the use of old indicators is possible even if made in the 1960s. While K&E had their main office and factories in Hoboken through 1968, this slide rule was probably made in Connecticut at their Salisbury plant.

2010.007.0018

2010.007

Lukacs, Claire

Gift

Museum Collections. Gift of a friend of the Museum.

1950 - 1967

Date: 1950-1967

Good

Notes: Picker X-Ray Fetal Medical slide rule, instructions for use of the rule transcribed from back: 1. Select the arrow label with the correct target-film distance and move this arrow to the previously determined* ([footnote] *See Fig. 1 and 2 and Instruction Booklet.) object-film distance on Scale A. 2. Move the hairline to that figure appearing on Scale E which represents the pelvic diameter or the cirumference of the fetal skull as measured on the film; the corrected value is now shown by the hairline on Scale D. 3. If the hairline also intersects Scale B-1. the volume capacity of this corrected diameter is shown on this scale in terms of a sphere. 4. Having obtained the corrected circumference of the fetal skull in both AP and lateral projections, determine the average of the two figures which is the MEAN CIRCUMFERENCE. Set the hairline on the figure on Scale D which represents this MEAN CIRCUMFERENCE and read the volume of the fetal head on Scale B-2 which is corrected to include the scalp. 5. The hairline in step 4 intersects Scale C and indicates the approximate fetal age in weeks correlated with the mean circumference of the fetal skull, as adapted from Hodges' Modification of the Scammon and Calkins formula." 1a. (Caliper method for use with metal ruler). Move slide until image of 10 cm. long metal ruler or of 10 divisions of a graduated cm metal marker fits between caliper pointers and proceed with step 2, 3, 4 and 5 as above. (Valid for any target-film distance). Prepared for use with Ball's Method of Cephalo-pelivitry by Gerhart S. Schwarz, M.D. [end] _____ [cataloguer's notes] The dangers of damage to fetuses and their mothers from x-ray radiation was an area of study in the mid-twentieth century. At the time that this item was produced, a concensus was developing that x-ray radiation was not appropriate for this purpose. As ultrasound imaging (along with other image technologies) was being introduced and maturing as a common tool that would replace the need for routine x-rays, this slide rule was soon to be unncessary. X-rays were still needed for certain medical conditions, but not for the typical measurements that this slide rule would facilitate. Status: OK Status By: dw Status Date: 2010-04-13

front, full view
detail indicator detail right end with calilper closed and fully extended; company logos back, full view details back text: left half (top); right half (bottom) Slide rule: Picker X-ray Fetal Medical, made by K&E Co., [Hoboken], n.d., ca. 1950s-1967. picture number 6