APPENDIX. 425 



further shows that the latter form one series with the Savian 

 bodies and the so-called muciparous canals of osseous and car- 

 tilaginous Fishes. We ventured, in the paper in question, to 

 add the "tactile hairs" or "vibrissa" of Mammalia to this 

 series of cutaneous organs, by showing that they are but a 

 further development of the muciparous canals — pointing out, 

 at the same time, that even the highest organs of sense, the 

 Eye and the Ear, are constructed upon the same principle. 



§2. 



Malpighian bodies of the spleen. — Having recently carefully 

 investigated the structure of these organs, we have arrived at 

 the following conclusions (vid. l Quarterly Journal of Micr. 

 Science/ Jan., 1854). 



I. In the various animals examined (Man, Sheep, Pig, Rat, 

 Kitten), we find, as Dr. Sanders had already demonstrated in 

 the Pig, that the minute arterial twigs supplying the Malpighian 

 bodies are not only distributed over, but enter and ramify in 

 them, breaking up into their fine penicillate branches as they 

 pass out. 



Furthermore, connecting these arterioles, there is a network 

 of fine capillaries, whose walls are hardly distinguishable, but 

 which are readily detected by using syrup, which retains the 

 colouring matter in their contained blood-corpuscles. 



The pulp of the Malpighian body stands, as Remak pointed 

 out, in the relation of tunica adventitia to the arterioles ; it is 

 composed of indifferent tissue, consisting of endoplasts im- 

 bedded in a homogeneous periplast, and which may or may 

 not become surrounded by cell-walls. 



The Malpighian body has no wall, but passes insensibly, as 

 Wharton Jones had already shown, into the fusiform fibres of 

 the red pulp. 



We adduce evidence from Remak and Leydig that the 

 Malpighian bodies of other Vertebrata present similar relations, 

 and that the spleen, lymphatics, Peyer's patches and the 

 glandula solitaries, the supra-renal capsules, thymus, and pitui- 

 tary body, belong to the category of the so-called "vascular" 

 glands, all consisting essentially of masses of indifferent tissue 

 contained in a vascular plexus. 



We proceed to show that the follicles of the tonsil are not 



