145
subjected to the influence of the noxa of the disease. These being under daily medi- cal inspection and supervision the first signs of Beri-beri were carefully sought for and noted if found. An exact record was made and shews a very wide varia- tion from 31 days' exposure to 103 days. As we do not know exactly the period of incubation, nor with any certainty what are the symptoms which mani- fest themselves during this incubation period, we must include the incubation period in this period of exposure.
We found the first signs. shew itself as follows:-
2 cases in
''
31 days.
33
11
1
37
市场
>>
53
J
58
>"
14
17
1
6) 68
"
1 case in
1
72 days. 78
13
J
1
84
11
21
1
፡፡
90
93
79
103
39
77
>>
We may justifiably conclude that a lengthened period of exposure is necessary in order to contract the discase.
Recurrence or Re-infection and Relapse.
Beri-beri is a disease which does not confer immunity upon those who have suffered from it. Indeed one attack of it may be a predisposing cause for another attack and perhaps to repeated attacks. We were informed by a medical man that he knows a patient, a doinestic servant, who contracts it regularly every year for the past 18 or 20 years. The proportion of cases of re-infection is about 1 in 10
or 12 cases.
With reference to the question of a relapse, we are of opinion that relapses do not occur and that cases classed as such are really cases of re-infection.
The Cause of Death.
Death may occur from heart failure principally, or from some sub-acute or acute pulmonary complication. It may sometimes ensue with appalling sudden- ness. A patient who may apparently be progressing favourably and may shew signs of a favourable issue may without warning succumb to cardiac failure. On the other hand the disease may drag a slow length towards an unfavourable termi- nation. The dry form of Beri-beri becomes steadily worse, the general atrophy progressively becomes more intense, until death ensues.
Acute infectious diseases may sometimes supervene ou Beri-beri and be fatal- small-pox. plague and enteric are known to occur. Malaria also co-exists and may prove fatal. In point of fact the majority of cases of Beri-beri which are of a chronic or sub-acute nature are liable to be infected with any other disease.
Prophylaxis.
In order to prevent the outbreak of Beri-beri amongst people who are liable to be confined in buildings for any period of time the following measures should be adopted :-
(1.) The buildings should be well ventilated.
(2.) There should be no overcrowding.
(3.) The food supply should be ample in quantity and of good quality.
(4.) The drainage should be perfect.
(5) The buildings should be so constructed as to get all the sunshine
possible.
(6.) Damp in the buildings should be avoided.
(7.) The inmates should have regular exercise in the open air.. (8.) The greatest personal cleanliness should be ensured.