The Structure and Functions of the h?emolymph Glands and Spleen. 19 



Silver nitrate impregnation has been used in particular cases, and 

 Heidenhain^s iron alum method in addition to sa/franin, in combination 

 with light green or gentian violet, to demonstrate nuclear figures and 

 other cell details. Hœmalum and eosin have been employed in the 

 case of almost all glands for purposes of comparison, because they 

 give so good a contrast between adenoid tissue and blood sinus. This 

 combination is further particularly well adapted to cases where phago- 

 cytosis is to be studied. Saffranin in conjunction with a suitable plasma 

 stain, gives very beautiful results after hardening the material stained 

 in Flemming^s solution. The aniline Blues have been useful in prepa- 

 rations of reticulum. 



VI. Minute structure. 

 1. Microscopic Anatomy of a typical hœmal gland. 



It will be advisable to give in the first instance, a description 

 of the minute structure of a typical blood-red hsemal gland, such as 

 one meets with in the ox or sheep, and to subsequently note the points 

 of difference between the histology of this type, and that of other 

 varieties. The general arrangement of the tissues has already been 

 described by previous observers; a short account will consequently 

 here suffice. 



This account may be conveniently given under the three headings, 

 1. Capsule and Trahecidae, 2. Sinuses, 3. Adenoid tissue. 



The adenoid tissue lies for the most part towards the centre of 

 the gland, and is of irregular form, for it is cut up by the '^central 

 sinuses", which communicate with the ^^peripheral sinuses" lying im- 

 mediately beneath the capsule. The central sinuses are chiefly in the 

 form of offshoots from the peripheral sinus, and they frequently com- 

 municate to form an irregular network in the centre of the lymphoid 

 mass. The greater area of sinus, as seen in sections, belongs to the 

 peripheral portion: this again is limited externally by a strong ''cap- 

 sule'^ from which numerous fibrous processes or ''trabeculae" project 

 inwards, running into the adenoid tissue and further subdividing it. 

 As a general rule these trabeculae, when present, are accompanied by 

 surrounding sinuses, and eventually end by breaking up into finer and 



