Large Number Of Operations Research Articles

Groups in which a large number of operators may correspond to their inverses

An abelian group may be defined by the property that, in an automorphism of the group, more than three fourths its operators may be placed in a one to one correspondence with their inverses.t It may be of interest to know the groups possessing the property that five eighths or more of the operators may be inade to correspond to their inverses. The principal object of this paper, however, is to establish the following elementary theorem (I) and to illustrate the use that may be made of it in certain problems. THEOREM I. A group that has two invariant subgroulps with nothing in common, but the identity can be set up as a nlzutiple isornorphisn?, between two groups of lower order. Let a group ( G ) of order k, k x have the two invariant subgroups K1 and K, of order k1 and k2 respectively. If K, and K2 have only the identity in comiimon, every operator of K, is commutative with every operator of K2. It may be assumed that G is not merely the direct product of K, ancl K2. Let 1, r2 r31 ** , be the operators of K-1 and 1 s2, s, ..*, those of K2. Now

NERVOUS AND MENTAL DISEASES FOLLOWING PELVIC OPERATIONS.

The topic assigned to me is a narrow one, namely, the nervous and mental diseases or changes which follow pelvic operations in women. The purpose of the inquiry is to show if there is any difference in the nervous and mental effects which follow operations upon the pelvic organs from operations done on other parts of the body or surgical operations in general. It would be easy to discuss this subject from one's individual experience, but it would be exceedingly narrow. The observations that come to any one man are certainly few as compared with those that come to a large number of operators, so that I shall not relate individual cases, but will draw conclusions so far as I can, from the literature which is accessible to me and the material which I have collected. The literature is disappointingly deficient in many respects. Reported cases of the nervous and

THE CAUSATION OF THE DISEASES OF WOMEN.Read in the Section of. Obstetrics and Diseases of Women, at the Forty-fourth Annual Meeting of the American Medical Association.

Within recent years activity among gynecologists has taken the form of improvement in the technique of operations; and as an outgrowth of the large number of operations which have been performed, the pathology of diseases of women has likewise been improved. Comparatively little has been written concerning the causation of the diseases of women, although the subject is one of great importance, in view of its bearing upon preventive medicine. Only as the causes of disease are made known to the profession at large, is it possible to take measures for their prevention. And in gynecology, especially, prevention is far better than cure. The principal causes of the diseases of women are: 1. Imperfect development of the sexual organs. 2. Gonorrhea. 3. Septic inflammation following child-birth. 4. Lacerations due to child-birth. 5. Miscellaneous causes, including constipation, erroneous habits of life, and errors of dress. 1.— Imperfect Development of the Sexual Organs .—