360 MR T. ARTHUR HELME ON HISTOLOGICAL OBSERVATIONS ON 



killed at various stages, from one to thirty-six days after parturition. The uterus was 

 removed while the circulation was still going on. It was then immediately divided into 

 pieces of suitable size, and plunged into one of the following fluids : — 



1. Saturated solution of picric acid. 



2. Solution of chromic acid, — £ per cent. 



3. Solution of osmic acid, — \ to 1 per cent. 



4. Midler's fluid. 



5. Absolute alcohol. 



Similarly, uteri of rabbits at various stages of pregnancy, the uterus of a virgin 

 rabbit, and that of a rabbit which had not borne for several months, were taken and 

 treated in a like manner. 



I have divided this paper into two parts — in the first, giving a resume of the general 

 literature showing our present position in regard to the changes in the human uterus and 

 that of lower animals ; and in the second, dealing with the rabbit and recording the facts 

 observed and conclusions come to by myself. I first give the general literature including 

 that of the human uterus, for a twofold object — first, to make clearer the points to which 

 I have directed my attention in the rabbit's uterus, and to contrast the process that 

 occurs in the rabbit with that said to occur in the human subject ; and secondly, to 

 anticipate my own work, as yet incomplete on the same subject. 



PART I. 



Literature of the Changes in the Human Uterus and that of Animals 

 during Pregnancy and the Puerperium. 



In reviewing the literature, it is convenient to consider separately the human 

 uterus and that of animals, and under each to take up (l) pregnancy, (2) the puerperium. 



I. The Human Uterus. 

 A. Pregnancy. 



1. Muscular Tissue. — The changes that take place in the uterine musculature and 

 connective tissue during pregnancy have, considering the importance of the subject, 

 received very meagre attention. Few observations are recorded, and these many years 

 ago. 



Kolliker asserts that the increase in size of the uterus is due to an increase of all 

 its constituent elements, the process in the musculature being two-fold, namely, 



a. A new formation of muscle cells. 



b. A hypertrophy of existing cells. 



