288 CARPENTER, ON HUMAN PHYSIOLOGY. 
within the basement-membrane during the act of absorption, from 
what he considered to be granular germs visible in the same situation 
during the intervals of the process; but there can now be little doubt 
that the appearance in question is really due to the distension of the 
cylindrical epithelial cells investing the 
villi with the lacteal fluid; and as it is a Fig. 22, 
matter of much interest to examine and ex- 
plain the mode in which absorption in this, 
its first stage, is effected, the attention of 
many observers has been directed to the 
structure of these cylindrical investing 
epithelial cells; and if the observations of 
Heidenhain Briicke be correct, our know- 
ledge of the mode of absorption of various 
substances, and especially of those of an 
oleaginous nature, will be materially sim- 
plified. According to these investigations,* 
the investing cells of the villi (c, Fig. 22) are 
of cylindrical form, with a ciliated border, 
and are filled with a clear sarcode contain- 
ing a bright ee fee cilia stand erect 
during life, but quickly disappear after ae afi 
death, being replaced by a globular swelling the ‘Orin of the Lage ane = 
projecting from the mouth of the cell, phe hs ia ne ko ie 
2 poe aps the per ee of beers communicating branches; “ Gi 
wide and free extremity of these cells is ated columnar epithelial cells, the 
supposed by some (Briicke) to be almost or chet extrait ol w}ich are 
prin sone amet ba closed ene eke nective-tissue-corpuscles. 
of sarcode-lke substance, whilst e 
and others consider it to be covered bya delicate septum perforated like 
a colander with extremely fine canals or pores. The small and attached 
extremities of these cells are believed to be prolonged into the interior 
of the villi, becoming continuous with the caudate processes of the 
corpuscles of the connective tissue (d) which constitutes the matrix, 
and which again open, as shown in Fig. 22, into the lacteal vessel (c), 
thus affording a direct means of entrance for the fatty matters into 
the absorbent system, and explaining the occasional introduction of 
solid particles into the circulating current.f 
* See Heidenhain in ‘ Moleschott’s Untersuchungen,’ band iv, 1858, p. 251; 
and Briicke in band viii, 1862, p. 495; and in ‘ Denkschrift. d. k. Akad. d. Wiss. 
zu Wien,’ band vi, p. 105. 
+ ‘ Physiologie,’ 1863, p. 365. 
t These epithelial cells were described by MM. Gruby and Delafond (*C 
Rendus,’ 1843, 1195), as possessing cilia on their free margin; but Kolliker and 
Funke considered this appearance as illusory, and produced by the thick 
membrane closing the free extremity of the cell being perforated by very delicate 
pores or canals, whilst after death it split up in such a manner as to resemble a 
bundle of cilia (Kélliker, ‘ Mikroskop, Anat.,’ 1860, p. 329). Balogh, agreeing 
with Kdlliker as to the lines in question being canals, differed from him in 
believing them to be not pre-existent, but merely the indications of the passages 
made by the molecules of fat in penetrating the delicate tissue occluding the 
mouth of the cell (‘Moleschott’s Unters,’ band vii, 1861, p. 556). Brettauer 
and Steinach, on whose observations the statements of Briicke, Heidenhain, and 
other later authors are founded (Brettauer and Steinach, ‘ Sitzungsbericht d. k. 
Akad. d. Wissen. zu Wien,’ 1857, band xxiii, p. 303), maintained that the 
apparent cilia were prolongations of the cell-contents, the cells themselves 
