354- 



STOMACH AND INTESTINE. 



this to occur, it is evident that such a remittent 

 contraction would not destroy the claims of 

 the absorptive act itself to be considered 

 the chief force which propels the chyle. For 

 in any case, the muscular apparatus would 

 but limit and remove that diatention of the 

 lacteal which absorption had previously ef- 

 fected. It would thus, as it were, merely re- 

 gulate and transfer the mechanical force of 

 the latter act ; so as to modify it, either 

 constantly, or at definite intervals of time. 



Some observers have attempted to verify the 

 action of this delicate muscular apparatus dur- 

 ing life. Gruby and Delafond first instituted 

 such observations on a variety of domestic 

 animals j and they have since been repeated 

 by Bruecke and Koelliker. AH of these 

 authorities agree in remarking an alternate 

 shortening and elongation of the vilius : a 

 change of form which is so rapid and marked, 

 that there need be little hesitation in attri- 

 buting it to a corresponding contraction and 

 relaxation of these unstriped fibres. But 

 the phenomena seen in the course of such 

 vivisections cannot be safely accepted as those 

 of the healthy animal in its natural state. * 



Such a caution is still more applicable 

 to those contractions by which the villi share 

 in that irregular movement of the intestine 

 already described as a kind of rigor mortis. 

 On exposing the villi of an animal soon after 

 death, they gradually become shorter and 



Fig. 263. 



Villi contracted and shortened so as to offer circular 

 or transverse wrinkles. From the small intestine of 

 the dog shortly after death. Magnified 100 diame- 

 ters ; and examined by reflected light. 



wider ; at the same time that their surface 

 is generally thrown into circular transverse 



general this view of the action of unstriped fibre, I 

 must confess myself very reluctant to accept it on 

 its present evidence. 



* for, to say nothing of the pain, the irritation, 



wrinkles or folds. A more minute examination 

 shows that these folds consist of epithelium, 

 which has separated from the basement mem- 

 brane at the points that correspond to the 

 greatest projection between the contiguous 

 wrinkles (Jig. 264, 2.) A closer adhesion of 



Fig. 264. 



Similar villi as seen by transmitted light. The vilius 

 marked 1, has been partially withdrawn by con- 

 traction from its investing epithelium, which is thus 

 left entire like the finger of a glove. 



a, epithelium of the vilius; b, granular matrix or 

 substance of the same. 



those columnar cells which occupy the free 

 extremity of the vilius, frequently causes this 

 part to be defined, as a shallow funnel, by the 

 neighbouring separated cells. While in other 

 instances, a variable length of the whole vilius 

 withdraws from its cellular investment with 

 such uniformity, as to leave the extremity of the 

 latter empty, smooth, and uninjured (fig. 264, 

 1.), like the finger of a glove. Frequently, how- 

 ever, some of the epithelial cells are detached. 

 It is obvious that all these appearances 

 are referable to a contraction of the un- 

 striped fibres within the vilius, withdrawing the 

 substance of the latter from its epithelial in- 

 vestment. The movements which often ac- 

 company these changes resemble those above 

 mentioned as beheld during life ; and consist 

 of shortening or elongation, to which are some- 

 times added lateral displacements. The date 

 of their occurrence is limited to the period 



and the exposure, which are involved in such an 

 opening into the intestine as is necessary to allow a 

 proper inspection of the villi, Gruby and Delafoud 

 remark, that their surface becomes wrinkled and 

 pale at the time of their contraction. Such circum- 

 stances imply so much disturbance of these soft 

 structures, as to throw great suspicion upon any 

 view which would interpret them as part of a normal 

 process. 



