SEMINAL TUBES OF TESTICLE. 



279 



Dissection. With the view of examining the investing fibrous 

 coat, let the testis be placed on its outer side, viz., that on which the 

 epidiclymis lies, and let it be fixed firmly in that position with pins. 

 The fibrous coat is to be cut through along the anterior part, and 

 thrown backwards as far as the entrance 

 of the blood-vessels. While raising this 

 membrane a number of fine bands will 

 be seen traversing the substance of the 

 testicle, and a short septal piece (medias- 

 tinum) may be perceived at the back of 

 the viscus, where the vessels enter ; but 

 it will be expedient to remove part of 

 the mass of tubes from the interior 

 (fig. 104), to bring more fully into view 

 the mediastinum, and to trace back some 

 of the finer septa to it. 



The tunica albuginea, or the fibrous 

 coat of the testicle, is of a bluish-white 

 colour, and resembles in appearance the 

 sclerotic coat of the eyeball. This mem- 

 brane protects the secreting part of the 

 testicle, and maintains the shape of the 

 organ by its dense and unyielding struc- 

 ture : it also sends inwards processes to 

 support and separate the seminal tubes. 

 These offsets of the membrane appear in 

 the dissection ; and one of them at the 

 back of the testicle, which is larger than 

 the rest, is the mediastinum. 



The mediastinum testis (corpus High- 

 morianum, fig. 104, r,} projects into the 

 gland for a third of an inch with the 

 blood-vessels. It is situate at the back 

 of the testis, extending from the upper 

 nearly to the lower end, and is rather 

 larger and deeper above than below. It 

 is formed of two pieces, which are united 

 in front at an acute angle. To its front 

 and sides the finer septal processes are 

 connected ; and in its interior are con- 

 tained the blood-vessels behind, and a net- 

 work of seminal ducts (rete testis) in front. 



Of the finer processes of the tunica albuginea (fig. 104, 6) which 

 enter the testis, there are two kinds. One set. round and cord-like, 

 but of different lengths, is attached posteriorly to the mediastinum, 

 and serves to maintain the shape of the testis." The other set forms 

 delicate membranous septa, which divide the mass of seminal tubes 

 into lobes, and join the mediastinum, like the rest. 



Within the tunica albuginea is a thin vascular layer, the tunica 



How to see 

 the struc- 

 ture of the 

 testis. 



FIG. 103. THE TESTIS, WITH 

 THE TUNICA VAQINALIS 

 LAID OPEN. 



of the 



a. Testicle. 



b. Globus major 

 epididymis. 



c. Corpus Morgagni. 



d. Parietal part of the 

 tunica vaginalis. 



e. Vessels of the spermatic 

 cord. 



/. Vas deferens. 



and 



finer septa : 



a vascular 

 layer lines 



