Martin Motor Co., 76 Ga. App. 456 (46 S. E. 2d 197); J. C. Lewis Motor Co. v. Williams, 55 Ga. App. 538 (69 S. E. 2d 816); Kuhr Brothers v. Spahos, 89 Ga. App. 855 (81 S. E. 2d 491).

2. The allegation contained in the petition that: "Said tires constituted a danger obvious only to persons with scientific knowledge as to the proper manufacture thereof, and with knowledge as to the actual manufacture thereof, which knowledge was possessed by defendants but not by plaintiff," was not only tantamount to, but was a direct averment of knowledge on the part of the defendant, and ignorance of the plaintiff of the defect in the chattel furnished by the former for the use of the latter.

3. The petition contained an allegation that the use of the chattel in its defective condition proximately caused certain injuries sustained by the plaintiff, and such other factual averments as were necessary to set forth a cause of action.

4. "An allegation as to the knowledge of the defendant of a certain state of facts is not demurrable as a conclusion." Georgia Power Co. v. Blum, 80 Ga. App. 618 (57 S. E. 2d 18).