Revisiting Castlio and Ferris-Swift's experiments on direct splenic stimulation in patients with acute infectious disease.

Background: In 1934, Yale Castlio, DO, and Louise Ferris-Swift, DO, published the results of a within-subjects experiment on direct splenic stimulation in patients with acute infectious disease (N=100). Their results, which used rudimentary statistical analyses, are still cited as evidence that osteopathic manipulative treatment augments immunity.

Objective: To retest the validity of Castlio and Ferris-Swift's conclusions by applying contemporary statistical methods to their raw data.

Methods: Castlio and Ferris-Swift's original 1934 data were not normally distributed and sample sizes were small. Therefore, the authors of the present study reanalyzed the data using several nonparametric statistical methods: Wilcoxon signed rank, Friedman, and Kruskal-Wallis tests.

Results: Contemporary statistical analysis confirms a modest posttreatment increase in leukocytes, a decrease in erythrocytes, a decrease in the Arneth index, and an increase in reticulocytes after the application of direct splenic stimulation for patients diagnosed with acute infectious disease. Contemporary reanalysis also confirms statistically significant posttreatment changes in the immune function tests. Findings were less conclusive for the leukocyte differential cell counts and for the effect of varying the number of splenic compressions.

Conclusions: Analysis of Castlio and Ferris-Swift's 1934 data using contemporary statistical methods supports many of their original conclusions. However, faults in study design common to that era limit the article's applicability for modern researchers. Additional research on splenic pump techniques using contemporary study designs and statistical methods is recommended.