While both parties presented medical testimony in regard to this issue, neither side produced the one doctor who is shown by the record in this case to have examined the plaintiff after both occurrences. In view of these circumstances it was not error under the decision of this court in Beardsley v. Suburban Coach Co., 83 Ga. App. 381, 390 (8) ( 63 S.E.2d 911) for the trial court to submit the above principle of law in charge to the jury. See also Morgan County v. Glass, 139 Ga. 415 ( 77 S.E. 583).

Within the space of six or seven months after the collision a chiropractor and two doctors treated him for injuries sustained in the collision. Though it could be fairly inferred that the testimony of these witnesses might have been material in proving the amount the plaintiff was entitled to recover, none of them were produced as witnesses nor their absence accounted for. While a party need not account for every witness who has knowledge of facts pertinent to his cause or defense ( Southern Ry. Co. v. Acree, 9 Ga. App. 104 (2) ( 70 S.E. 352), where the testimony of available witnesses is material to his cause or defense, the witnesses must be produced or the inference will arise that their testimony would be unfavorable to the party who fails to produce them. Price v. Whitley Construction Co., 91 Ga. App. 257, 268 ( 85 S.E.2d 528); Beardsley v. Suburban Coach Co., 83 Ga. App. 381 ( 63 S.E.2d 911); Weinkle Sons v. Brunswick Western R. Co., 107 Ga. 367, 373 ( 33 S.E. 471); Savannah, Fla. Western Ry. v. Gray, 77 Ga. 440, 443 ( 3 S.E. 158); Stevenson v. State of Georgia, 83 Ga. 575, 581 ( 10 S.E. 234). While the charge was not an accurate statement of the rule as to when the presumption provided by Code § 38-119 arises, in that it omitted reference to the statutory provisions that the presumption exists when the evidence the party fails to produce will repel a charge against him (is material to his cause or defense) or where the evidence the party introduces is inferior to that he fails to produce.

A common carrier has the duty to exercise extraordinary care to protect passengers on its vehicle. See McBride v. Ga. Ry. Electric Co., 125 Ga. 515, 516 ( 54 S.E. 674), and Beardsley v. Suburban Coach Co., 83 Ga. App. 381 ( 63 S.E.2d 911). There are numerous other decisions to the same effect. Counsel for the defendant relies on the theory that the plaintiff's wife did not use proper care for her own safety; that she could have asked the operator to check the door to see what was wrong; that she could have used the front door as a means of egress; that she used excessive force to open the back door and thus she was the author of her own injury. Counsel cites Mansfield v. Richardson, 118 Ga. 250 (3) ( 45 S.E. 269) wherein the Supreme Court said: "In cases of personal injuries, the plaintiff as a conscious human agent is bound to exercise ordinary care to avoid the consequences of the defendant's negligence, by remaining away, going away, or getting out of the way of a probable or known danger.

Ground 9 concerns the reading of excerpts from medical textbooks; grounds 17 and 20 concern requested charges on pain and suffering. All of these grounds relate to the right to, or the amount of, damages, and any errors therein are harmless to the plaintiff since the verdict for the defendants could only have been returned on the theory that there was no liability. This being so, the question of the amount of damages, to which all of these grounds refer, was not before the jury for consideration. These special grounds are accordingly unnecessary for consideration. Beardsley v. Suburban Coach Co., 83 Ga. App. 381 (9), 392 ( 63 S.E.2d 911). 3. Special ground 6 contends that the court "committed reversible error in withholding from the jury plaintiff's exhibit No. 5 against the demand of movant and in making the comments pertaining thereto of a prejudicial nature to movant as set forth in this ground."

If any amplification of the general principles of law, which the charge contained, had been desired they should have been made the subject of an appropriate and timely written request. Beardsley v. Suburban Coach Co., 83 Ga. App. 381, 393 (11) ( 63 S.E.2d 911). 2.

We next consider the issue as to the charge of the court on the presumption arising from the failure to produce evidence. See Beardsley v. Suburban Coach Co., 83 Ga. App. 381, 391 ( 63 S.E.2d 911), wherein this court said: "A party is not required to produce all witnesses; he may rest his case upon one witness, though another be accessible; but he subjects himself to the presumption arising from failure to so produce. Southern Ry. Co. v. Acree, 9 Ga. App. 104 (2) ( 70 S.E. 523). . . While it is true that this principle is not applicable to criminal cases ( Whitley v. State, 14 Ga. App. 577 (5), 81 S.E. 797; Jones v. State, 14 Ga. App. 811, 82 S.E. 470), . . . it is true that in civil cases it may be a duty on the part of either party to the cause, where he has evidence in his power and within his reach by which he may repel a claim or charge against him, to produce it or suffer the presumption that the charge or claim is well founded. This rule applies irrespective of the burden of proof.

In dealing with an attorney-client privilege, the Massachusetts court stated in Phillips v. Chase, 201 Mass. 444, 450, 87 N.E. 755, 758: Burch v. Reading Co. (E. D. Pa.) 140 F. Supp. 136, 164; Blackstone v. Osche (W. D. Pa.) 192 F. Supp. 174, 176; Ferne v. Chadderton, 363 Pa. 191, 198, 69 A.2d 104, 108; Secondino v. New Haven Gas Co. 147 Conn. 672, 674, 165 A.2d 598, 600; Fenstermaker v. Bodamer, 195 Pa. Super. 436, 171 A.2d 641; Pawlowski v. Marino, 71 N.J. Super. 120, 176 A.2d 488; Keener v. Fidelity Cas. Co. (La.App.) 96 So.2d 509; Peoria Life Ins. Co. v. Smith (E. D. Mich.) 47 F.2d 279; Beardsley v. Suburban Coach Co. Inc. 83 Ga. App. 381, 390, 63 S.E.2d 911, 918; O'Connor v. City of Detroit, 160 Mich. 193, 125 N.W. 277; Dodge v. Dobson, 21 Wis.2d 200, 124 N.W.2d 97. "* * * [I]f evidence is material and competent except for a personal privilege of one of the parties to have it excluded under the law, his claim of the privilege may be referred to in argument and considered by the jury, as indicating his opinion that the evidence, if received, would be prejudicial to him."