90 CARNEGIE INSTITUTION OF WASHINGTON 



the estrous cycle. In the glands of the uterine mucosa, however, cilia are 

 always present and appear to be equally active and numerous at all periods 

 of the cycle. The observations were made upon bits of uterine and tubal 

 mucosa taken from freshly killed animals and flattened down under a cover- 

 slip. Under these conditions, with low powers of the microscope, the cilia 

 could be seen actively beating, the motion continuing for several hours even 

 at ordinary room temperature and without the addition of any special fluid. 

 Sections of fixed tissue taken from the same material showed the characteristic 

 histological structure of the cilia. In this manner it was possible to demon- 

 strate that cilia are present in the tubes and in the uterine glands, but never 

 on the surface of the uterus. Furthermore, there is never any significant 

 variation in the number or activity at different stages of the cycle. We must 

 therefore assume that, in the uterus of the pig at least, the cilia can play no 

 important part in the transport of the ova, as has been frequently suggested, 

 but must be associated with some other function. In fact, from what we 

 know from Dr. Corner's studies on the internal migration of ova, the latter 

 are able to move against any currents produced by the uterine cilia, whatever 

 the direction of these currents may be. 



Ovarian Follicles. 



Working with Dr. Corner, M. S. and A. F. Guttmacher have studied the 

 wall of the mature Graafian follicle of the sow and have been able to prove, 

 by physiological measures as well as by morphological criteria, that there is 

 an abundance of typical smooth-muscle cells in the theca externa. In some 

 places these cells form solid bands of muscle, in others they exist only in 

 scattered groups in the follicular wall. It is interesting to note that where 

 the follicle has been freshly ruptured the arrangement of the muscle-fibers 

 suggests that they in some way take part in the rupture; that is to say, they 

 do not remain as a passive membrane on the periphery, but project along with 

 the other layers as finger-like processes into the contracted follicular cavity. 

 Proof that these fibers function as smooth muscle was established by cutting 

 out a strip of the living follicular wall and suspending it in a warm bath of 

 oxygenated Locke's solution, so that by means of a writing lever an accurate 

 record of its contractions could be obtained on a smoked drum. Under these 

 conditions, when the strip was stimulated by the addition of a solution of 

 barium chloride, records were obtained which were typical of smooth muscle. 



These investigators succeeded also in demonstrating the presence of auto- 

 nomic nerves with typical motor endings in juxtaposition to the smooth-muscle 

 cells. Furthermore, they have shown that the innervation is similar to that 

 of the musculature of the intestine; that is, the nervous mechanism of the 

 follicle responds to the action of a drug which stimulates fibers of the true 

 sympathetic system, causing a relaxation of the smooth-muscle fibers. On 

 the other hand, by the use of other drugs, the presence of a para-sympathetic 

 innervation and the contraction of the ovarian musculature were demonstrated. 



From these experiments it is not possible to say that the smooth-muscle 

 of the ovary is responsible for the periodic rupture of the follicles. The 

 investigators were not able to produce contractions sufficient to induce rup- 

 ture by any of the methods of stimulation used. They worked with excised 

 organs and it is possible that, if similar experiments could be conducted in 

 the living animals, fruitful results might be attained. At any rate, it is 



