On the existence of cell communications between blastomeres

Abstract

Several years ago in following the development of the larval excretory organs of the SerpulidEupomatus, I had in the course of the investigation to section a large number of the gastrula stages of the egg of this worm. From time to time, in some of these sections I noticed delicate strands of protoplasm traversing the segmentation cavity or portions of this space, connecting one cell with another, or one blastomere with its neighbour. These connections were similar in many respects to the “filose” strands described by Andrews (1), which he has observed joining the blastomeres, in a number of Metazoan eggs during life. I also noticed they were sometimes present in advanced stages where their filose character was somewhat different from their appearance at an earlier date. I paid them little attention at first, considering them the result of the action of the fixing reagent in coagulating the albuminous fluid of the blastocoel, or what was still more probable, to the imperfect penetration of the reagent, and the consequent necrosis and disintegration of the protoplasm in the interior of the egg. Meeting with them again and again in the course of the work, and under conditions that seemed to show they were not due to either of these causes, I was led to make a few experiments to determine if possible their nature and significance. Their presence, I found, was well marked, in eggs preserved with any of the good fixatives, especially those that act rapidly, such as the Osmic acid mixtures, and Corrosive-acetic. The action of these is sufficiently different to preclude the strands being therefore of the nature of ordinary coagulation artifacts. On the other hand, it was impossible to ascribe them to the breaking up to the protoplasm and imperfect fixation, as in many of the eggs in which they were present all the finer histological details were well preserved, and in some cases the various phases of mitosis plainly shown.