326 The Philippine Journal of Science 1922 
creased considerably from the age of 8 years up to the adult 
period. The females, as a general rule, showed a greater num- 
ber of positive reactions than the males; they averaged 14 per 
cent of the total number of females examined, whereas the males 
only showed 5.8 per cent of positives. We also noted similarity 
in reaction in several groups of brothers and sisters in the 
Government Orphanage; and where differences were found, the 
younger ones gave the positive reactions. 
TaBLE 1—Schick reaction in Filipinos. 
Rigeee 
Male. Female. Total. 
Age. 
Cases. Positive. Cases. Positive. Cases, Pcsitive, 
Years. Cases. | Per ct. Cases. | Per ct. Cases. | Per et. 
Dees than 3 22263 q 5 71 3 1 83 10 6] 60 
py Save onaenae OBE Ae Ry 5 5 val 2 1 50 9 6 | 66.6 
og MRE SE eae 10 3 80 6 4 66 16 7 43.7 
U0 see 16 5 81 4 2 50 20 7 35 
CAG Soc a 9 1 11 20 6 30 29 i i eas 
re aU ees wae Sa 80 0 0 20 3 15 50 3 6 
<p it: RSE, 57 1 1.7 20 0 0 17 1 1.3 
ih ge Ee ee Pe 102 2 1.9 37 6 15 139 8 5.7 
Oe Mics Bone 163 1 4.2 25 3 12 188 10 5.3 
Ty oe) SEBO eek eater 95 5 5.2 16 3 19 111 ca lly FD 
| 18andover..-.......... 202 YT G8! ip, el ee 
3 Se 698 41 5.8 832 47 14/ 1,080 88 | 8.5 
Zee 
Comparing our findings with those of other authors (Table 
2) we find about the same figures as regards the percentage of 
positive reactions from the age of 8 years downward; but from 
8 years upward there is a definite decrease of at least two- 
thirds in the number of persons showing positive reactions as 
compared with the results in other places. Assuming that the 
Schick reaction is an index’ of the susceptibility of individuals 
toward diphtherial infection, we must conclude that Filipino 
children are just as susceptible to diphtheria as are children in 
other places. Boys and girls of school age and adults, on the 
other hand, compared with individuals of the same age in Hurope 
and America, are very much less susceptible to the disease. 
The relatively low susceptibility of Filipinos as a whole can- 
not explain entirely the relatively rare incidence of diphtherial 
disease in the Philippines. Evidently there must be other fac- 
tors that must be taken into consideration ; for instance, climate 
and such other conditions as may also influence the relative 
infrequency in the Tropics of other diseases, such as serious 
respiratory disturbances, etc. 
