Many kind of researches have been made for the cause of the formation of liver cirrhosis and recently the relation between the spleen and the cause has been the subject of discussion. But there are many points that are not come to light yet. The author has made an investigation about the significance of the reticulo-endothelial system and spleen-hormone relating the rise of this disease. By looking ober the experimental methods of study that have been made, he can divide them in to four classes:- 1. To put in various kinds of medicines. 2. To give special or one and the same kind of food for a long time. 3. The bile duct and ligature of the veins that enter and leave. 4. To give bacteria and their products. As inflammatory poisons, among other things, alcohol, chloroform, phosphorus, arsenic, tar, adrenalinemia, decoction of tobacco-leaves, antimony arsenite, and etc. have been used for a long time. But lately it is reported that carbon tetrachloride was used to give rise to liver cirrhosis. Mr. Midorikawa injected 0.05cc. carbon tetrachloride as the quantity for a day into rabbits respectively for dozens of times over and made the image of liver cirrhosis in the liver. Mr. Paul Ramson, and Mr. Kubo have reported that they got the same result. As for the author, he injected 0.6cc. oleum olivarum which contains 20% of carbon tetrachloride per kilogram weight of body respectively into the male rabbits weighing some 1.5kg. each and accomplished the study. Experiment I.To research for the significance of the general reticulo-endothelial system in relation to the cause of this disease, first he made an experiment of reticulo-endothelial blocking that is to say, he made 1% collargol solution by Mr. Amano's method; and injected 0 65cc. of it into each rabbit through their ears' veins per kilogram weight of body. After that he detected the ebb and flow of reticulo-endothelial function for same days by using trypanblue solution by Mr. Adler-Reimann's method. This experiment made it sure that the quantity of collargol which was used in it reduced the function to the weakest state next day and it recovered 3 as usual after 14days.Thus given two groups of stout rabbit were used in this experiment. The first group were injected with collargol solution and next day with carbon-tetrachloride. Into the second group he injected carbon-tetrachloride first and collargol solution next day. After four days killed them all, he extirpated their livers, fitted them with 10% formalin solution, made cutting preparation gave various dyeing to them and detected the change of the disease.The result. of the experiment shows apparently addifference between the results of the two groups; that is, both of them showed degenerative metamorphosis of liver but the change of the first is far greater than that of the second. Next, the same experiment done ober every fifteenth day for a long period showed still the same result as that above mentioned.This proves that the perpection or the imperpection of the reticulo-endothelial function has an important significance relating the change of liver disease. Experiment II.The author made the following experiment to know the significance of spleen relating the cause of the formation of the experimental liver cirrhosis.Given four groups of rabbits were used in this experiment. The first group are stout ones as a standard; the second group whose spleens were extirpated six days ago; the third group who were once extirpated their spleens cleanly and soon made auto-transplantation in their bellies six days ago; the fourth group whose spleen were extirpated 45days ago. He injected 0.6cc. oleum olivarum which contains 20% carbontetrachloride into the above mentioned four groups of rabbits respectively per kilogram weight of body and after four days killed all of them and compared their liver cirrhosis in the same way. The period of 45days after the extirpation of spleen is the time when abolition in the function of spleen is to be compensated. By the result of the above experiment, clear distinction can be found out between the first group and the second group; namely, the change of the liver disease of rabbits after extirpation of spleens is in far higher degree than that of stout ones. But those of the third group and the fourth group are very slight and rather come near to that of the first group.This proves that the existence of spleen has an important significance in relation to the rise of this disease.Experiment III.Lately the study of internal secretion spring into existence and it was proved that spleen is one of the internal organs that do the internal secretion and that spleenextract contains spleen-hormone which is said chiefly to acts on reticulo-endothelial system. In order to examine the effect which spleen-extract works on the rising of this disease, he made the following experiment. First to detect how spleen extract works on stout rabbit, he injected 1.0cc. of 25 times diluted spleen-extract (Prepare:- see the authors thesis, "The biochemistric-study of spleen-extract") into the ears' veins of the first group for three days in succession per kilogram weight of body, and for the second group, as a standard, he injected 0.85% salt solution into them in the same way and the next day injected 0.6cc. oleum olivarum which contains 20% carbon-tetrachloride into the both groups per kilogram weight of body and killed them after four days and compared the change of the liver disease in the same way. Though the result of this experiment shows little difference between the first group and the second group, he found that the change of the former is comperatively less than that of the latter.Next he repeated the same experiment on the rabbits who were extirpated spleen six days ago and got the result of great difference between the first group and the second group; that is to say, the change of the disease in the case of injecting spleen-extract into the spleen extirpated rabbits was far slighter than that in the other case and was nearly in the same degree as that of ordinary rabbit. But, as a standard, in the case of injecting them with only 0.855% salt solution first and then carbon tetrachloride, the change of the liver disease was in exceedingly high degree. Again he made an experiment in the same way on the rabbits that were extirpated their spleen (6days) ago and blocked completely the rest of reticulo-endothelial cell by injecting their ears' veins with large quantity of 0.8cc. collargol solution per kilogram weight of body for three days in succession. And the result of it made a clear distinction between those of the first group and the second group; namely, the change of the disease of the rabbits that were injected with spleen-extract was far slighter than that of those who were injected, simply as a standard, with 0.85% salt solution.The author repeated the same experiment on the rabbits that were extirpated spleens six days ago, by using chloroform (to give through mouth 0.5cc. of it per kilogram weight of body) and "Nekoirazu" (to give through mouth 0.05 gram of it per kilogram weight of body).By this it is sure that the changes of the disease by injecting with spleen-extract are all slighter than those of the standard examples. And these experiments make it clear that spleen-hormone has an important relation to the cause of the formation of the experimental liver cirrhosis.From the experiments above mentioned the author has obtained the following conclusions:-I) The general reticulo-endothelial system relating the cause of the formation of the experimental system liver Cirrhosis has a fixed relation. That is, when the function of the general reticulo-endothelial system is imperfect or the spleen is abolished, the invasive poison attacks the livercells sooner and heavier.II) The change of the disease above mentioned is exceedingly lighten by the transplantation of spleen piese and the injection of spleen-extract. That is, the special substance of spleen (HORMONE-) has an action to be able to reduse the change of the liver by poison through the general reticulo-endothelial system, especially Kupper's star-cell.