Neurohistopathological investigation was carried out on the brains and spinal cordsof 105 newborn chicks which, judging from epidemiological aspects, symptoms, andhistopathological findings, were believed to have been infected with a disease identicalwith what had been reported under the name avian encephalornyelitis. The resultsobtained are summarized as follows.1) MaterialsThe materials used for the investigation consisted of 105 chicks which had beencollected from 11 poultry farms (named A -K), as recorded in Table 1. The birds werefrom 5 to 42 days old and were broiler chicks of foreign-produced strains. In all ofthem, except four, weakness or paralysis of the legs was recogrnized as the mainsymptom. Tremor in the head and neck was found only in a few of them.2) Histopathological findings of brains and spinal cordsa) Degeneration of nerve cells (Figs. 1810) : This change was observed mosteasily and clearly in large ntotor nerve cells. The nerve cells swelled, and their cytoplasmwas stained pale, showing a homogeneous feature. The Nissl substance disappeared inmost part, altlrough it frequently remained in the periplreral areas of tlte cell bodies.There were often enlargement and peripheral migration of the nucleus in these cells.It may be said that suclx changes were in progress in the process of degeneration. In thefinal stage, the nerve cells formed an irregular-shaped mass or a shrunken mass stainedwell with eosin. Irn this way, the dernsity of nerve cells became very low in the nuclearareas, such as the ventral horns of the cervical and [urnbar en[arc>ement of the spinalcord, which otherwise were to be rich in large unotor nerve cells. The process ofdegeneration of small nerve cells seemed to be fundamentally identical with that oflarge nerve cells. On the whole, however, the frequency of appearance of affected nervecells was usually low.b) Activation of neuroglias: The activation of neuroglias was very dull, ascompared with the changes of the nerve cells, especially the large nerve cells wlaichshowed outstanding features of degeneration. In fact, the neuroglias were almost in-different to the degeneration of large nerve cells. On the other hand, a feature namedneuronophagy occurred here and there to degenerated small nerve cells, but it was notso important as the other Iesions. Rather than that, the sparse accumulation of micro-glial cells scattered in the groutad substance attracted more attention. On that occasiondegenerated nerve cells could, or could not, be demonstrated near the cellularaccumulation.c) Appearance of wandering cells: This finding was also infrequent. It was animpressive feature, however, that plasma cells had infiltrated here and there into theground substance of gray matter.d) Vascular changes (Figs. lIsI6) : There was a slight Iesion in which a fewplasma cells had infiltrated into perivascular spaces. This Iesion needed attention.Vascular alteration was a [esion of small blood vessels observed in older birds, whichexhibited a cellular accumulation, thick or thin, surrounding a part of the blood vessel.The cellular elements recognizecl were mainly histiocytes, lymphocytes, and plasma cells.Moreover, microglial cells were oftern fottnd in such lesion. Such vascular lesionsappeared in no particular areas.3) Distribution and severity of affected nerve cells and neurogliasLesions were investigated in all parts of the brain.and spiztal cord, and comparedas systematically as possible. Tlte results are sltown in Table 2.a) Large nerve cells: In view of the cellular constrtuction, the areas coming intoquestion were Nucleus (N.) isthmi, pars magnocellularis, N. ruber, Nn. ocu[omotoriidorsalis et ventralis, N. reticularis pontis caudalis, pars gigantocellularis, and variousnuclei in the ventral horns of the spinal cord. Judging from the distribution andseverity, the cervical and lumbar enlargement of the spinal cord attracted an over-whe[ming attention, followed by N. [the rest omitted]

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前報13)において,初期ニワトリ胚にたいする低酸素圧気体環境の催奇形作用を,6日胚について観察した.本報では,各胚令の胚に施す低酸素圧処理条件に,致死率を基準とした一定の生物学的力価を持たせ,各胚令の奇形学的反応性の比較を行ない,さらに胚令18日の胚について,初期胚に施した低酸素圧処理が,後期の器官形成にいかなる影響を及ぼすかを検討した.胚令0.5日より6.0日までの各胚令の白色レグホンの胚にたいして,正常気圧下で,N2および02混合ガスにより,3~8時間の低酸素処理を加えた.処理条件は,胚令18日で50%の生存胚が得られるものとした.胚令18日目に開卵し,外形異常を観察した後,骨格標本を作成し,骨格異常を検索した.得られた結果は次の通りである.1.胚令の進行にともない,低酸素圧気体環境にたいする胚の抵抗性は減弱し,胚令18日目に50%の生存率を得るには,より高い酸素濃度が要求されたくTablcsl,2),2.外形異常として,頭蓋破裂と外脳症が胚令1.0および1.5田こ処理した群に,小および無脳症が胚令2.5~3,5日処理群に,小および無眼球症が1.0~4.0日処理群に,角膜突出・眼瞼欠損・口蓋欠損および外鼻孔異常が胚令3.0~3.5日処理群に,四肢の異常が胚令3.0~4.5日の処理群に,いずれも高率に認められ,奇形学的時期特異性が観察された(Table4,Chart2).3. 骨格系の異常は,胚令1.5~4.5出こ処理した各群に高率に認められた(Table5,Chart3).脊椎骨の異常は,胚令1.5日の処理群では顆椎の頭側に,2.0日処理群では顆椎の尾側より胸椎の頭側部に,′2.5日処理群では胸椎の尾側および腰仙椎の頭側に,3.0日処理群では頚椎と腰仙尾椎に高率に観察された.すなわち3,0日処理群の顆椎の異常を除けば,脊椎骨の異常の所在が,処理した時期に対応して,頭側より尾側に移動する傾向が認められた.これはまた低酸素圧処理を施した時点における体節の分化位置と一致するものであった(Chart.4).四肢骨の異常は,胚令3.0~4.5日処理群に認められた.処理時の胚令が進むにつれて,異常部位が近位部骨から遠位部骨へと移動する傾向が観察された.

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ニジマスの心電図と呼吸運動を無線的に記録し,魚類の生態研究に新しい技術を導入することを企図し,その基礎的な実験を行なった.成績の概要はつぎの通りである.1)脊髄穿刺により不動化した後,開胸し,心表面誘導による波形を記録した.穿刺による出血は,従来の記載に反し,極めて微量であった.静脈洞,心房,心室波の波形はBAKKER(1913),KIscH(1948),OETs(1950),NOSEDA(1963)らの記載とほぼ一致した.この成績に基づき,ラジオ・テレメーターの入力として用いる心電図の誘導方法を決定した.この誘導法は,一種の胸腔内誘導であるが,電極装着後,2ケ月以上を経過しても生存した.波形は唾乳類,鳥類などと同様であったが,まれにBAKKERのV波を確認した.2)水温と心拍数の相関々係はおよそ直線的であった.水温の上下に比例して,心拍数は増減したく水槽内).3)中禅寺湖で水温の垂直分布に従って,計測した心拍数は温度の下降に比例して減少したが,水温の上昇に追従できなかった.実験槽で行った実験結果から考えられる適応時間を与えても同様であった.4) 中禅寺湖に放流したニジマスにつき,水深50m,水温4.3°Cまでの心拍数をFM式ビート・メーターにより計測した.水温の変化による心拍数の変動は,実験室内でえた成績とほぼ同様であった.5)養鱒池に放流したニジマスにつき,心拍数の日周変化を計測した.心拍数は早朝に少なく,午後ないし夜間に増加した.因みに水温は9.5°Cを維持していた.

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Corynebacteriumrenaleの3つの型では,アミノ酸および発育素要求性に差異があることをさきに述べた.この報告では,各型のminimummcdiumを確立し,なおfilamcntousgrowthについて記述する.各型C.renaleのminimummcdiumの基礎培地の組成は全く同じで,1750M燐酸緩衝液pH7.4,塩化ナトリウム,塩化カリウム,硫酸アンモニウム,重炭酸ナトリウムおよびブドウ糖を含む.アミノ酸および発育素に関して以下に述べる.I型菌のminimummcdiumは,glutamicacidおよびva11ncの2種アミノ酸に,biotin,panto-thenicacid,thiamineおよびinositolの4種発育素を含む.II型菌のそれは,glutamicacidにb10tin,nicotinicacidおよびP-aminobcnzoicacidを必要とする.III型菌のminimummcdiumは,glutamicacid,va11ne,cystinc,isoleucineおよびmcthionineの5種アミノ酸のほかに,pyridoxinc,thiamine,biotin,nicotinicacidおよびglucosamincを含み,IおよびII型に比較して,より複雑な成分を必要とした.minimummediumに発育した3つの型の菌は,集落の大きさおよび形態は,普通寒天に発育した集落のそれと変わりなく,また抗原性にも変化がなかった.上記の実験中に,無機イオンの欠乏および過剰による本菌のfilamcntousgrowthが観察された.FC++は3つの型の菌に共通に,必須的に要求される.IIおよびII工型菌は,FC++低濃度では,通常の菌形の4~5倍の長さを持つfilamcntousformを示し,FC++高濃度では,球菌状になった.Mn++,Mg+1およびCu+1も,最適濃度範囲外の濃度では, filamentousformをもたらすが,特にIIおよびIII型に著明であった.

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The influences of epidural anesthesia exerted upon the flexor reflex, the kneejerk, and the evoked potential of polysynaptic reflex were observed in dogs. The evokedpotential that had been produced by electrical stimulation to the N, cutaneus suraecaudalis was recorded from t[te M. gastrocnemius in a dog under general anesthesia, The results obtained are summarized as follows.(1) Tlte flexor reflex and the knee jerk disappeared rapidly within about twominutes and recovered slowly after administration of the anesthetic.(2) The evoked potential disappeared within about two minutes after administra-tion of the anesthetic.(3) Tlaese reflexes disappeared almost at the same time when the f -S pointsbiased to the right side in the previous experiment.(4) In the dog under epidural anesthesia, the standing posture was maintained, with no sonaatic reflex activity shown by the hind limb.

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