1. A high meningococcus carrier-rate in a military unit denotes that dangerous overcrowding exists in this unit.

2. Severe overcrowding (i.e. when beds are less than 1 foot apart) is usually accompanied by a carrier-rate (serological) of at least 20 per cent.

(Twenty per cent. is the danger line indicated in the War Office Memorandum on Cerebro-spinal Fever, March 1917.)

3. A carrier-rate of this height will usually imply that the mobilization standard of 40 square feet has been infringed, and also that beds are less than 1 foot apart.

4. A carrier-rate of 20 per cent. (without awaiting the occurrence of any actual cases of the disease) should be regarded as a signal for prompt and effective action to abolish overcrowding, and to improve ventilation, and to increase the distance between the beds to at least 2½ feet.

5. The distance between beds is of paramount importance.

6. Carrier-rates of between 10 and 20 per cent. are unsatisfactory and imply a certain degree of overcrowding. They must be watched with suspicion, and the mobilization standard strictly enforced.

7. Under the same conditions of overcrowding “non-contact” carrier-rates are the same as “contact” carrier-rates.

8. Quite a moderate degree of “spacing out” of beds, combined with simple methods for improving ventilation are highly efficient agents in reducing high carrier-rates.

9. When, however, a unit shows a high carrier-rate, insistence on the restoration of the mobilization standard is not sufficient.

“Spacing out” must be carried further; and a distance of at least 2½ feet between beds insisted on.

The “peace” standard of 3 feet between beds and 60 square feet of floor space with 600 cubic feet of air space would, of course, be still more effective.

10. The mobilization standard, introduced for a grave emergency, is the lowest possible concession to military necessity, which can be allowed with safety.