Other Articles |


JAMA. 1945;129(11):741. doi:10.1001/jama.1945.02860450027009.
Text Size: A A A
Published online

In order to find a standard cell system for a study of the effects of DDT, Lewis and Richards1 of the Wistar Institute, University of Pennsylvania, made numerous tests of the possible toxic action of DDT on in vitro tissue cultures. In their preliminary tests a small drop of saturated alcoholic or acetone solution of DDT was allowed to dry on a cover glass. Hanging drop cultures of heart, brain, intestine and spleen from seven to eight day chick embryos or one day rats were set up so as to include the dry DDT. During the seven day observation period the cell growth, migration and mitosis of fibroblasts, entoderm and macrophages were not appreciably different from those in control cultures without DDT. As they moved about in the cultures living fibroblasts often touched or even migrated over DDT crystals without appreciable injury.

This apparent nontoxicity was confirmed with several


Sign In to Access Full Content

Don't have Access?

Register and get free email Table of Contents alerts, saved searches, PowerPoint downloads, CME quizzes, and more

Subscribe for full-text access to content from 1998 forward and a host of useful features

Activate your current subscription (AMA members and current subscribers)

Purchase Online Access to this article for 24 hours

First Page Preview

View Large
First page PDF preview




Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).


Some tools below are only available to our subscribers or users with an online account.

Sign In to Access Full Content

Related Content

Customize your page view by dragging & repositioning the boxes below.