SCIENCE 



NEW YORK, DECEMBER 2, 1892. 



IMMUNITY FROM LEPROSY OF THE FIFTH GENERA- 

 TION. 



BY ALBEKT S. ASHMEAD, M.D., NEW TOKK. 



There is a fact which, I believe, bears very directly and very 

 strongly upon the subject of non-contagion of leprosy. It is 

 recognized by all Oriental leprologists that every child of a leper 

 has an inheritance of the disease, but diminished, and that after 

 the fourth generation, if no healthy blood intervenes, the disease 

 is entirely extinguished. There is about these matters a very in- 

 teresting lave in China, and consequently in Japan, the latter 

 being, in spite of its western civilization endeavors, much more 

 submissive to Chinese traditions than to European ideas. I find 

 it expressed in Virchow's Archives by Dr. Friedel, in the follow- 

 ing words : — 



" No marriage with children of leprous parents is allowed. 

 If leprosy appears in a family formerly clean, all betrothals and 

 contracts of marriage previously entered into are rescinded as a 

 matter of course. Only when the betrothed or married persons 

 suffer of the same degree and type of leprosy, for instance, if they 

 are both of the fourth degree of generation, the alliance stands. 

 Only equal degrees of age of the morbid cases are allowed to con- 

 nect themselves by marriage. A leper of the fourth generation, 

 even if he no longer shows any external marks of the disease, 

 can only marry a woman of the same degree of age of the disease : 

 their offspring is free from leprosy, and no longer forbidden 

 human intercourse." 



Here we have, then, a perfect immunity acquired in four gen- 

 erations, and the fifth generation restores the health of the race. 

 There is certainly a connection between this extinction of the 

 disease and the present immunity of Europe, after that part of 

 the world had been a prey to leprosy during several centuries of 

 the middle ages. Evidently in the west, simple isolation has 

 unconsciously accomplished in the lapse of time what a rational 

 legislation tries to bring about in the east. This legislation has 

 probably preserved the populations of China and of the east in 

 general from entire destruction. I do not mean to say that the 

 rule is always and carefully adhered to, because in that case the 

 disease would be extinct now ; but the rule is sufficiently known, 

 and sufficiently adhered to, to make its salutary consequences 

 felt. 



Isolation then, and exhaustion of the pathological principle, 

 after the course of four generations, are the only methods known 

 to us of acquiring immunity. Wherever the disease still exists, 

 it is the violation of that law, with which all the Oriental priests 

 and doctors are so familiar, that has kept it alive. I had occa- 

 sion about a year ago to speak of these matters, at a time when 

 there was very much and very silly newspaper talk about the 

 danger arising from the presence of a few poor leprous Chinamen 

 in New York. I beg permission to reproduce here my whole ar- 

 ticle which I sent at that time to the Tribune, and which was 

 published Aug. 9, 1891. 



" The recent appearance of several Chinese lepers in New York, 

 and the fact that they are permitted to pursue their avocation for 

 a time, at least, among us, suggests to me the following points 

 which it may be useful to consider in our conduct towards indi- 

 viduals of that kind, which the abundant flow of immigration 

 may bring to our shores: 



"1. Leprosy in China is very frequent ; in the province of Quang- 

 tung, of which Canton is the capital, alone, there are at least 

 10,000 lepers; in all the maritime provinces of the South it rages 

 with the greatest intensity. It abounds, also, in Hankow, Cen- 

 tral China. Outside of Canton, in its province, there are many 



leper villages, also along the Yang-tse-Kiang, as has been noted 

 by several European observers. As to the interior of China, our 

 knowledge of leprosy, of course, is derived solely from indigenous 

 information. We kno^v that the disease is more frequent In 

 Quang-tung, Quang-sae, Hoonan, and Fuh-kun. In Pekin lep- 

 rosy is rare. It is a generally admitted fact that it has not spread 

 beyond the regions where it is established. Of course, it should 

 be a rule at San Francisco to obtain information as to the part of 

 China where the Mongolian immigrant comes from, if such a 

 thing is possible. At any rate, might not a certificate of health 

 be required of him? 



"2. The Chinese believe that the disease may be communicated 

 by the contamination of food. This generally received opinion 

 must seem to us strange at first; but the fact that the lepro- 

 bacillus is found in greater abundance in ttie mucous membranes 

 about the mouth, throat, and nose lends it a certain degree of 

 plausibility. Now, the Chinese established among us preserve, 

 as everybody knows, all the customs of their own country. One 

 of these customs consists in grouping together and eating their 

 rice from the same bowl with those chopsticks which are promis- 

 cuously used by the whole house. If there is really something in 

 the Chinese views of food infection, the necessity of isolating a 

 leper from his countrymen is evident. 



"3. The Chinese Government believes that leprosy is contagious, 

 but it does not seem as if the people shared in this belief. There 

 are asylums to isolate lepers all around Canton; laws and regula- 

 tions have been issued with the same views. Yet, in spite of the 

 regulations, the leper may enter any city by paying a certain sum 

 of money, which goes to the leper fund. Altogether the Chinese 

 act as if they did not believe in contagion. Nobody thinks of 

 refusing to buy from a leprous huckster; provisions are bought 

 fearlessly in the store of a leprous caterer. The disease, we may 

 therefore admit, cannot easily be communicated by contact. Yet 

 if there is any danger in contact, then we may be sure that the 

 Chinese among us, true to their traditional customs, as they are, 

 will do nothing to diminish it. 



"4. But even the Chinese believe, with many other Eastern 

 nations, that leprosy is communicated by cohabitation. Their 

 laws recognize this fact. Some strange superstitions show how 

 much the people are convinced of it. It is a belief among the 

 leprous women of China that a woman affected with leprosy can 

 be cured by cohabitation with healthy males. Whether we ad- 

 mit the Chinese theory, or are inclined to doubt it, we cannot ab- 

 solutely condemn it, and therefore should not legal obstacles be 

 put in the way of such intercourse between the two races? At 

 any rate a leprous Chinese should under all circumstances be sent 

 back to his own country. 



" 5. To allow the leprous male intercourse with healthy women 

 is simply to strengthen and nourish the lepro-bacillus. The 

 strength of the latter is gradually attenuated as lepers breed with 

 other lepers, so that after a certain number of generations the 

 obligate parasite is extinguished. This is the law of hereditary 

 transmissibility, which has influenced all Oriental legislation, 

 inasmuch as mai-riage between recognized lepers is permitted, 

 while between a leper and a healthy person it is prohibited. This 

 tendency to further disease, produced by the admixture of healthy 

 elements, may not be apparent at the first forthcoming genera- 

 tion. The disease sometimes skips a generation or two and re- 

 mains latent, until the third or fourth, perhaps, it meets with 

 susceptible material. As long as there is a leper here, unre- 

 strained in his actions, there is evidently danger of his perpetuat- 

 ing the disease among us. 



"6. It must not be believed that we are absolutely and under 

 all circumstances safe from leprosy. It is true that European 

 residents in China, even where their contact with the natives is 

 very close, catch the disease only when they un-Europeanize 

 themselves altogether, that is, eat and live with the natives on 



