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CONTINUITY OF LIFE 



diagnosis, prognosis, and even prevention 

 of a wide variety of diseases. For example, 

 in attempting to diagnose what was causing 

 a patient to vomit blood, the doctors de- 

 cided it must be one of two things, ulcers 

 or liver disease. Elaborate laboratory tests 

 revealed that neither of these seemed to be 

 the cause. One of the physicians recalled 

 that the father of the patient had shown a 

 tendency to bleed due to the fragility of 

 his capillaries in local lesions. Because this 

 condition is controlled by a dominant gene, 

 the likelihood of a similar condition appear- 

 ing in the son was good. By an exploratory 

 examination of the stomach the suspected 

 diagnosis was verified, the region of capil- 

 laries giving the trouble was removed and 

 the case was cured. Here a knowledge of 

 genetics was very helpful in solving a prob- 

 lem which probably would have continued 

 to be a mystery to the physician and a 

 source of discomfort to the patient. 



Of equal and perhaps greater importance 

 is the use of genetics in the realm of prog- 

 nosis. Young married people or those about 

 to be married often wish to know what 

 the probabilities are for them to have nor- 

 mal children. This is particularly important 

 to those who have some so-called "taint" or 

 "skeletons in the closet" in their family. 

 Sometimes advice is sought for on the posi- 

 tive side, that is, they wish to know what 

 the chances are for them to transmit certain 

 talents to their offspring. One case will 

 illustrate the importance of such informa- 

 tion. In a family of five children, two boys 

 were severely crippled by serious muscular 

 disease; the others, two girls and a boy, 

 were normal. The problem that concerned 

 the parent was the chance of this disease 

 appearing in the next generation. After 

 careful analysis of the situation it was evi- 

 dent that the gene causing the difficulty 

 was sex-linked. Therefore the father must 

 have had a normal X chromosome (AY) 

 while the mother must have carried the 

 defect in one of her X chromosomes (Aa). 

 The boys showing the affliction must ac- 



cordingly have been oY, whereas the nor- 

 mal son was like his father (AY) and the 

 daughters might or might not have had the 

 defective gene (Art or AA). The normal 

 son would, of course, be unable to transmit 

 the defect to his children. The daughters, 

 on the other hand, had an even chance of 

 picking up the defective gene from their 

 mother. Such information is highly valuable 

 to intelligent people because they can make 

 their decisions in the full light of scientific 

 fact rather than blind faith. The field of 

 medical genetics is just beginning and can- 

 not fail to become eventually a most fruitful 

 part of medical science. 



EUGENICS 



Eugenics is the study of race improve- 

 ment or the "science of being well born." 

 Certainly, man who has done so much in 

 improving his domestic plants and animals 

 should be able to do something about 

 improving his own combination of genes. 

 It would seem that all he has accomphshed 

 in a material way is useless if he stands idly 

 by and allows his own protoplasm to de- 

 teriorate with each succeeding generation, 

 yet some human genticists tell us that is 

 actually what is happening today. Some au- 

 thorities estimate (Fig. 24-21) that by the 

 year 2000 the 12 per cent of people we have 

 today with an I.Q. of 115 or better will have 

 been reduced to 7 per cent, and the present 

 2 per cent below 70 (moron, etc., group) 

 will have doubled their numbers. The situa- 

 tion might not be quite as grave as these 

 figures would indicate because we know 

 that some of the progeny of the more intel- 

 ligent will have lower I.Q.s than their par- 

 ents and some of the children from the less 

 able group will be brighter than their par- 

 ents. Even though there is only a slight loss 

 in our intellectual heritage, we should make 

 every effort to combat this downward trend. 

 Is there any way that this can be done? 

 Perhaps so, but many difficult problems pre- 

 sent obstacles. 



