TUBERCULOSIS AND SEGREGATION. 
By ALICE LEE, D.Sc. 
(1) In his book The Prevention of Tuberculosis (London: Methuen, no date 
on the issue we have used) Dr A. Newsholme has examined the influence of 
segregation on Tuberculosis. This is the topic of Chapter xxxv. In the opening 
of this chapter, he writes : 
The exact measure of iustitutional segregation of phthisis is the ratio stating how many of 
the total days' of sickness (number of patients and number of days of sickness) are passed in 
institutions. This ratio and the equivalents for it which have to be used in practice may 
for convenience be called the segregation ratio. The need for equivalents for the ratio as stated 
above arises from the fact that we are dealing with actual recorded experience, and the material 
has to be taken from the records as they happen to exist, (p. 266.) 
After noting the incompleteness of the records, Dr Newsholme continues : 
It becomes necessary therefore to select other figures which vary approximately with the total 
days of tuberculous sickness and the total days of tuberculous sickness passed in institutions, 
(p. 266.) 
We shall discuss below what "indirect measures of segregation" Dr Newsholme 
selects, but he gives the following most proper caution with regard to them : 
In using these indirect measures of institutional treatment of tuberculosis and of its pre- 
valence it must be remembered that they are indirect and approximate. Thus, for instance, 
figures for institutional treatment usually give the number of cases and not days of treatment, 
and while they tell how many people were segregated in institutions do not show the average 
duration, still less the quality of the treatment. Any of these indirect forms of segregation ratio 
has therefore to be verified wherever possible by the application to the same community and 
period of one or more other forms of the ratio, and checked wherever practicable by a special 
examination of sarnjjle constituent communities whose figures are included in the total, (p. 268.) 
Dr Newsholme in the course of his chapter gives a number of very high 
correlations between the phthisis deathrate and the indirect forms of the segre- 
gation ratio he has selected, and he interprets these as well as a long series 
of graphs as demonstrating that institutional segregation has been a most 
important factor in the diminution of the phthisis deathrate. Now any two 
variates which are changing continuously with the time — say, the consumption 
