細胞學家。浙江鎮(zhèn)江人（今寧波市）。1921年畢業(yè)于同濟醫(yī)工專門學校醫(yī)預科。1928年獲德國土濱根大學自然科學博士學位。中國科學院生物物理研究所研究員、名譽所長。在豐年蟲中間性的性轉(zhuǎn)變過程中，觀察到細胞重建現(xiàn)象；對雞胚早期發(fā)育、小鼠造血系統(tǒng)（骨髓）、根瘤菌和沙眼衣原體進行了細胞重建的研究；特別是在豐年蟲和雞胚早期發(fā)育中，證明以卵黃顆粒為基礎或細胞質(zhì)為基地，重建為細胞，是客觀存在的現(xiàn)象，并從卵黃顆粒中提取出染色質(zhì)。早年對線蟲生活史、個體發(fā)育、細胞常數(shù)、再生、染色體結(jié)構(gòu)和行為，甲殼動物色素細胞在不同溫度和不同濃度眼柄激素影響下的活動情況，搖蚊幼蟲變態(tài)過程中咽側(cè)體和心側(cè)體結(jié)構(gòu)與功能變化以及環(huán)節(jié)動物再生、再生與自然分裂關(guān)系、不同溫度下分裂與解體關(guān)系進行了研究。

1955年被選聘為中國科學院院士（學部委員）。

Cytologist. Born in Zhenhai, Zhejiang Province, Graduated from the premedical course of Tongji Medical and Tcchnical College in 1921. Received Sc.D. from Tuebingen Uneversity, Germany in 1928.Research professor and honorary diredtor, Institute of Biophysics,Chinese Academy of Sciences.

During the intersex changing of Chirocephalus, Bei observed the phenomenon of cell reformation and investigated cell reformation in early development of chick embryo, hemopoietic system of mice (bone marrow), nodule bacteria and Chlamydia trachomatis. He proved that the existence cell reformation is an objective reality, especially in the yolk granules and cytoplasm of early development of Chirocephalus and chick embryo and extracted chromatin from yolk granules.Formerly, he studied the life history, development, cell-constancy,regeneration, structure and behavior of chromosomes of nematode. He also studied chromatophore activity of crustacean in relation to different temperature and different concentrations of Eyestalk-extract, structural and functional changes of Corpus allatum and Corpus cardiacum of Chironomus larvae during metamorphosis, and annelid regeneration,relation between regeneration and natural fission, relation between fission and disintegration at different temperatures, etc…

He became Member of the Chinese Academy of Sciences in 1955.