The spleen is anatomically and physiologically a very complicated organ which has, among other things, destructive action on foreign erythrocytes when they are induced into the blood stream. Recently, much attention has been focuced on the pathological condition of spleen specially related with the iron metabolism, immunity and embryonic tissure construction. Clinically, on the other hand, the spleen often shows its abnormality by means of enlargement or atrophy in various diseases such as some infectious disease, Cacheia, malaria and hemophyliasis. The genesis of this abnormality is still in confusion.

Arthus (1) in 1903 injected horse serum repeatedly into the subcutaneous tissue of a rabbit and after 4 successive injections or more at intervals of several days found the animal reacts with acute inflammation at the site of injection; the skin about the injection becomes red, edematous and occasionally necrotic. Same result was obtained in the case where the preliminary injection was performed into the peritoneum. Arthus (1) first called this phenomenon "Local Anaphylaxis". This experiment has been fully verified in human beings by Pirquet (4). He called it as of the same nature as allergy. The tuberculin test is one of the clinical applications of this phenomenon. Confronting the general anaphylaxis, the local anaphylaxis has been studied topographically in various organs.

Lucas (3) and Gay (3) observed the same local anaphylatic phenomenon on the skin of children; Asada (6) observed in both skin and mucous membrane while Migikawa (7) observed on the testicles, lungs and muscle tissue. Apparently no one studied the local anaphylatic phenomenon on the spleen.

Recently, the problem of local immunity or local production of antibody has been a target of investigation and many investigators have proved that the site which produces antibody is not confined to those blood forming organs but any other organs, specially there is much relation with the reticulo endotheylian system.

There is no doubt that the spleen is one of the main organs which produce antibody. As Pfeiffer and Merx (4) already pointed out there is an abundant bacteriolysin in a rabbit's spleen in the earliest stage of immunity against Colera. If spleen plays an important part in the formation of antibody, there might be a close relationship between spleen and local anaphylaxis. Thus I have undertaken a careful observation on the local anaphylaxis of spleen by means of injecting antigen directly into the splenic artery.

Normal rabbits weighing about 2.000 Gm. were used for this study. The antigen used in this study is made freshly by the Sanitary laboratory, Chosen Government General.

Rabbits were sensitized by the injection of horse serum 2 cc into the abdominal subcutaneous tissue and the same dose was repeated every day for 4 days in succession. On the 15th day reinjection was made by means of an operative intra-splenic arterial injection of horse serum 0.2 cc. The rabbits were devided into 4 groups and spleen was removed for examination on the 1st week, 2nd week, 3rd week and 4th week respectively. The spleen was fixed immediately in the 10% formalin solution. The stains are the hematoxylin-eosin stain, the Sudan III stain, and the Hemosidelin pigment stain.

In this study, the spleen removed one week after the reinjection by means of serum injection into the splenic artery in the sensitized rabbits, shows histologically moderate atrophic condition of follicles, hypertrophy of connective tissure around the follicles. In some, necrobiotic change can be observed. In the splenic stroma vascular congestion and dense hyper-trophied troberculae lienis with yellow brownish pigment can be found. In the 2nd week, after the reinjection, the spleen shows more atrophied follicles and many follicles have lost their original shape and nature. Some of them are destroyed. Lymphocytes are numerously found and many of them are atrophied. In the stroma the blood vessels are congested and the traveculae lienis moderately thickened. The yellow brownish pigment in this stage is much diminished. In the 3rd week, the follicles are atrophied slightest degree and many newly formed follicles are found with the hyperplasty of new capillaries. In the splenic stroma the changes are similar to the state of the 2nd week but the yellow brownish pigments are much diminished in this week.

In the 4th week, the histological picture shows very little change from this normal picture. The yellow brownish pigment are still present in this stage.

Regarding the local immunity of spleen, there are many reporters such as Okasaki (8) but very little has been done on the splenic local anaphylaxis. Heineke, Ziegler (9) Sibudani (10) and Ono (11) observed the changes in the spleen histologically after X-ray stimulation on the spleen. Soper (12) and Kitaoka (9) by the vital staining found spleen showed the early destruction of lymphocytes. In the stroma the venous sinus dilated, vascular congestion, and proliferation of wandering cells. Tokumitsu (15) observed the changes of liver and spleen after the operation morphological by which the varous parts of vena cava were communicated with the postal vein. 150 days after the operation the splenic follicles showed decrease in number and much atrophied, the troberculae lienis and the splenic membrane are thickened. Some of them showed hyalin degeneration. In my study, the histological changes mainly the follicular atrophy, vascular congestion and degenerative changes of lymphocytes are possibly due to the fact that the aimphylatio toxin are more abundantly found in the antibody forming organs such as spleen.

The lipoid substance in the 1st week after the reinjection shows a slight diminution from the normal deposit, on the 2nd week the diminution is more prominent and on the 3rd and 4th week it was nearly negative. In my result thus far in the splenic local anaphylatic the animal shows gradual diminution of lipoid substance in the spleen absolutely not related with the general nutritional condition.

The Hemosiderin pigment in the 1st week more abundant than the normal spleen. In the 2nd and 3rd week it shows somewhat less in amount but still more than normal. In the 4th week it is still present and slightly more than normal. It is well known fact that spleen contains iron element. Lubarsch (9) insisted the content of iron element in the spleen has no relation with the iron content in the diet. Miwa (14) atributes this evidence to the fact of erythrocytic destruction in the spleen. Tokumitsu (15) observed same increase of hemosiderin in his experiments above mentioned and Sibudani (10) and Kitaoka (9) found an abundant hemosiderin pigment to the spleen after the X-ray stimulation, they attribute this evidence to the fact that X-ray provokes the process of destruction of erythrocytes in the spleen.

In the process of splenic local anaphylatic it is quite possible that the anaphylatic toxin produced in the spleen might stimulate the physiological erythrocyte destructive action of spleen.