164 WILLIAM WALLACE. 



does it project beyond the general internal surface of the 

 ovary. After the follicles in the ovigerous pouches have 

 ruptured, and the ripe eggs have escaped, the pouches 

 become drawn out into long clavate villi, whilst their 

 vascular and connective tissues undergo considerable hyper- 

 trophy. The walls of the ovary at this time are hypera3mic, 

 and the cavity contains an albuminous fluid. Red as well as 

 white blood-corpuscles are present in this fluid, the former in 

 great numbei's. From these facts Stuhlmann inferred that, 

 at the beginning of each gestation, the ovary passes into an 

 inflamed condition, as a result of which an exudation from 

 the blood of a nutritious albuniinous fluid and a diapedesis of 

 red blood-corpuscles takes place. The exciting cause of the 

 inflammation is the retention in the ovary of the eggs and 

 embryos, Avhich then act as foreign bodies. In this way 

 inflammation, which in general is a pathological pheno- 

 menon accompanying some specific disease, has, in the case 

 of the ovary of Zoarces, become a normal periodic pheno- 

 menon, on the occurrence of which the maintenance of the 

 species depends. 



As to the function, if any, of the red blood-corpuscles in 

 the metabolism of the foetuses, Stuhlmann considers that the 

 latter derive the oxygen for respiration from them. The 

 corpuscles pass along with the nutritious albuminous fluid , 

 into the alimentary canal of the fcetus, and while, in Stuhl- 

 mann's judgment, the fluid is absorbed in the short small 

 intestine, the red corpuscles are disintegrated in the 

 enormously hypertrophied terminal portion of the gut, the 

 rectum or '*end-darm." The oxygen thus set free from the 

 corpuscles is taken up by the blood-vessels in the walls of 

 the rectum. This portion of the gut, therefore, functions as 

 a kind of I'espiratory organ (!) (Stuhlmann, p. 42). 



The histology of the general wall of the ovary is as 

 follows: — The outermost layer is a single one of flat peri- 

 toneal epithelium. Next is a relatively thick coat of smooth 

 muscles. In this layer run arterial blood-vessels, and also 

 lymph-spaces lined with endothelium. The lymph-cavities 



