204 EPITHELIAL GLOBULES. 



umph : it will be found to resemble closely that of Reckling- 

 hausen if we carefully distinguish, as he does, what he calls the 

 secretion canals (lacunae) from the plasmatic cells. In France, 

 this opinion has been adopted by Rouget : he considers the 

 lymphatic vessels at their origin, in full communication with 

 the vacant spaces, the interstices of the tissues. Compara- 

 tive anatomy shows us, in the inferior animals, circulations 

 which are merely those in lacunae (sipunculi), and of which, in 

 the superior animals, the only traces are found in the cavernous 

 sinus for blood, and in the lymph spaces for the lymph. On 

 the other hand, the peritoneum must be considered as the re- 

 mains of what constitutes, in the inferior animals, the general 

 cavity of the body (between the external integument and 

 the internal integument, or the mucous membrane used in 

 digestion) : now in the superior animals the lymphatic sys- 

 tem still communicates freely, by small openings, with the 

 peritoneal cavity; as was first demonstrated by Reckling- 

 hausen. Having placed milk, or some pulverulent substance 

 in suspension in a fluid, on the diaphragmatic surface of the 

 peritoneum, he found that the drops of fat or other granula- 

 tions passed the epithelial layer at certain points; exami- 

 nation of the peritoneal serous membrane, by the aid of 

 nitrate of silver, convinced him that these points correspond 

 to special pores, situated between the cells of the peritoneal 

 epithelium (of the phrenic portion), and leading to lacunae 

 which form the commencement of the lymphatic vessels of 

 the diaphragm. These facts have been verified in Germany 

 by Ludwig, Schweigger-Seidel, Dybrowshy, Dogiel, etc.; the 

 same experiments were successfully repeated by Rouget, 

 who found that spontaneous injection of colored particles 

 took place in the lymphatic vessels of the diaphragm, when 

 these substances were injected into the peritoneal cavity of 

 the living animal ; Ranvier also found that they penetrated 

 these pores, when placed on the abdominal surface of the dia- 

 phragm of an animal lately killed. 



Recent investigations by Ranvier, however, seem to show 

 that the orifices by means of which this absorption is produced, 

 far from being open when in their natural state, open only at the 

 moment when the reabsorbed particles pass through. The 

 arrangement of these orifices is not plain, as yet! they were 

 supposed to exist in all parts of the peritoneum (Schweigger- 

 Seidel and Dogiel), and even in the mesentery ; but, on 

 resuming the subject, Ranvier became convinced that there 

 are neither absorbing mouths nor stomata in these parts, but 



