THE HARVEIAN ORATION. 735 



It gives a figure of the lacteals injected, by the means just specified, 

 as they exist upon the terminal segment, here widely globular, of 

 the ileum, upon a single disciform patch upon the commencing 

 colon, and, finally and chiefly, upon and all around the walls of the 

 colossal vermiform appendix of the rabbit. In this latter place it is 

 but what the Germans call, and have called (Frey, « Das Mikroskop 

 und die mikroskopische Technik,' 4th ed. 1871, p. 255), a Kinder- 

 spiel, to insert the point of the fine Einstichung syringe charged 

 with the soluble blue injection just beneath the peritonal coat at 

 the caecal end or elsewhere, when, upon pressing the piston, 

 a reticulation of blue will spread itself over the surface of the tube, 

 enclosing as islands the solid substance of the Peyerian follicles. 

 It needs but a little perseverance in the way of gentle pressure to 

 cause superficial tubular lymphatics to arise into view, and to 

 declare their true character by their contrast with and distinctness 

 from the blood-vessels, as well as by their moniliform character 

 speaking of their richness in internally placed valves. Passing 

 over the convex walls of the appendix, they join larger trunks 

 which run along its mesenteric border ; these larger trunks in 

 their turn enter the mesenteric glands, and form in their substance 

 reticulations strikingly like those formed previously in the walls of 

 the intestine around the solid substance of the Peyerian follicle — 

 suggesting thus to the naked eye the similarity, and by consequence 

 the homology, which a microscopic examination enables us to prove 

 to exist between the lymph-sinuses and the solid masses they 

 surround in the Peyerian follicles and in the mesenteric glands 

 respectively ^. 



It is the demonstration of the relation of the lymphatic or lac- 

 teal vessels, or sinuses, as the case may be, in different animals, to 

 the solid ampulla-like mass in the Peyerian follicles which the 

 modern method of puncture can claim as being eminently its own 



^ I take this opportunity of expressing my surprise that Henle has not seen his 

 way towards accepting this view of the real nature or Bedeutung of the Peyerian 

 follicles. In his ' Gef asslehre ' of 1868 (p. 404) he refers us back to his 'Eingeweide- 

 lehre,' p. 57, of 1862, where, as also in the second edition, 1873, p. 62, the absorbent 

 character of these structures is denied, just as it was by Hyrtl in his ' Handbuch der 

 Topographischen Anatomie,' i860, p. 646, and by Teichmann, 'Das Saugadersystem,' 

 1 861, pp. 86-91. The view which I have adopted was accepted by a distinguished 

 Fellow of this College, Dr. Burdon- Sanderson, in the Eleventh Report of the Medical 

 Officer of the Privy Council for 1868, p. 96. 



