PREFACE. 



it need not be forgotten that the assistance we can give to donors when reporting 

 our findings is very largely contingent upon its preservation. It is true that in the 

 course of time, and even now to some extent, we shall be able to give a report 

 suggestive of the possible intrauterine conditions from an examination of the 

 conceptus alone, and just in proportion as our knowledge of the condition of 

 the decidua increases this opinion will become more reliable, and hence also of 

 more practical value. 



The chief reason why the decidua, or the membranes, or the placenta are 

 not preserved oftener is that physicians have not fully realized that they are 

 needed and wanted. A mere reference to the protocols and summaries will illus- 

 trate in how large a percentage of the cases it is not included at present. Although 

 I fully realize that often it is impossible for the physician to secure it, and that in 

 other cases it is of little value even when secured, I am certain that the percentage 

 of cases in which it is missing can be greatly reduced in the future with consequent 

 mutual benefit. The closest cooperation with clinicians is necessary, not only 

 in order to secure the necessary material, but also to obtain further information 

 through supplementary observations upon the living patient. Only in this way 

 can the great gap left in human obstetrics and embryology, by the impossibility 

 of performing experiments, be partly filled. In the case of animals, experimentation 

 no doubt will eventually determine for us the relationship of teratology to path- 

 ology, but in the case of man this relationship must be determined very largely 

 by observation alone, for although every instance of human gestation under 

 abnormal conditions answers to an experiment, such experiments must always 

 remain uncontrolled, and the exact conditions which usually obtain must remain 

 unascertainable. Nevertheless, the practitioner, with the patient's help, frequently 

 can bear witness as to the conditions under which nature's experiment was per- 

 formed and as to the sequence of crucial events, and it is on the unselfish efforts 

 of physicians that we must depend for assistance in this matter. 



Mall did a very great service in calling attention to the fact that abnormalities 

 of the fetus are frequently associated with, even if not always or necessarily pro- 

 duced by, uterine diseases. The relationship between the two is revealed still 

 further, especially in Chapter IV, and further investigation of this subject ought 

 to bring to light facts not only of further scientific interest, but pregnant with 

 great humanitarian service. It is startling indeed to observe what a monstrous 

 fetus may accompany an apparently moderately diseased chorion, and it is equally 

 startling to observe that a chorionic vesicle apparently normal may be wholly devoid 

 of an embryo. But here we meet one of the obstacles in the way of present 

 progress, for we do not yet know exactly what a normal ovum or villus looks like 

 in all stages of development. Both must yet be standardized, and for this standardi- 

 zation a knowledge of the condition of the decidua and of the probable cause of the 

 abortion will be extremely helpful. If all early conceptuses were undoubtedly 

 normal, the problem would be a simple one; but very many are abnormal or 

 atypical at least. 



